Berkeley Hillside Preservation v. City of Berkeley , 60 Cal. 4th 1086 ( 2015 )


Menu:
  • Filed 3/2/15
    IN THE SUPREME COURT OF CALIFORNIA
    BERKELEY HILLSIDE                       )
    PRESERVATION et al.                     )
    )
    Plaintiffs and Appellants,   )
    )                          S201116
    v.                           )
    )                   Ct.App. 1/4 A131254
    CITY OF BERKELEY et al.,                )
    )                     Alameda County
    Defendants and Respondents; )                Super. Ct. No. RG10517314
    )
    DONN LOGAN et al.,                      )
    )
    Real Parties in Interest and )
    Respondents.                 )
    ____________________________________)
    The California Environmental Quality Act (CEQA) (Pub. Resources Code,
    § 21000 et seq.)1 establishes a comprehensive scheme to provide long-term
    protection to the environment. It prescribes review procedures a public agency
    must follow before approving or carrying out certain projects. For policy reasons,
    the Legislature has expressly exempted several categories of projects from review
    under CEQA. (See § 21080, subd. (b)(1) – (15).) By statute, the Legislature has
    also directed the Secretary of the Natural Resources Agency (Secretary) to
    establish ―a list of classes of projects that have been determined not to have a
    significant effect on the environment and that shall be exempt from‖ CEQA.
    1       All further unlabeled statutory references are to the Public Resources Code.
    (§ 21084, subd. (a).) ―In response to that mandate,‖ the Secretary ―has found‖ that
    certain ―classes of projects . . . do not have a significant effect on the
    environment‖ and, in administrative regulations known as guidelines, has listed
    those classes and ―declared [them] to be categorically exempt from the
    requirement for the preparation of environmental documents.‖ (Cal. Code Regs.,
    tit. 14, § 15300; see id., § 15000 et seq., Guidelines for Implementation of CEQA
    (Guidelines).) Respondent City of Berkeley (City), in approving a permit
    application to build a 6,478-square-foot house with an attached 3,394-square-foot
    10-car garage, relied on two of the class exemptions the Secretary has established
    pursuant to the Legislature‘s mandate: (1) ―Class 3,‖ which comprises the
    construction of ―new, small facilities or structures,‖ including ―[o]ne single-family
    residence, or a second dwelling unit in a residential zone‖ (Guidelines, § 15303);
    and (2) ―Class 32,‖ which comprises ―in-fill development‖ projects, i.e., projects
    that ―occur[] within city limits on a project site of no more than five acres
    substantially surrounded by urban uses‖ and that meet other specified conditions
    (Guidelines, § 15332).
    The Court of Appeal invalidated the permit approval, relying on Guidelines
    section 15300.2, subdivision (c), which provides: ―A categorical exemption shall
    not be used for an activity where there is a reasonable possibility that the activity
    will have a significant effect on the environment due to unusual circumstances.‖
    In the Court of Appeal‘s view, that a proposed activity may have a significant
    effect on the environment is itself an unusual circumstance that renders the
    categorical exemptions inapplicable. Finding substantial evidence of a fair
    argument that the proposed project may have a significant environmental impact,
    the court held that the exemptions the City invoked do not apply, and it ordered
    the trial court to issue a writ of mandate directing the City to set aside the permit
    2
    approvals and its finding of a categorical exemption, and to order preparation of an
    environmental impact report (EIR).
    We granted review to consider the proper interpretation and application of
    Guidelines section 15300.2, subdivision (c). We reverse the Court of Appeal‘s
    decision.
    I. FACTUAL BACKGROUND
    Real parties in interest and respondents Mitchell Kapor and Freada Kapor-
    Klein (applicants) want to build a large house on their lot on Rose Street in
    Berkeley. The lot is on a steep slope (approximately 50 percent grade) in a
    heavily wooded area. In May 2009, their architect applied to the City for a use
    permit to demolish the existing house on the lot and to build a 6,478-square-foot
    house with an attached 3,394-square-foot 10-car garage. The residence would be
    built on two floors, would include an open-air lower level, and would cover about
    16 percent of the lot.
    In January 2010, the City‘s zoning adjustments board (Board), after holding
    a public hearing and receiving comments about the project, approved the use
    permit. It found the project exempt from CEQA review under Guidelines
    sections 15303, subdivision (a), and 15332. The former, which the Secretary has
    designated Class 3, includes ―construction and location of limited numbers of new,
    small facilities or structures,‖ including ―[o]ne single-family residence, or a
    second dwelling unit in a residential zone,‖ and ―up to three single-family
    residences‖ ―[i]n urbanized areas.‖ (Guidelines, § 15303, subd. (a).) The latter,
    which the Secretary has designated Class 32, applies to a project ―characterized as
    in-fill development‖ meeting the following conditions: (1) it ―is consistent with
    the applicable general plan designation and all applicable general plan policies as
    well as with applicable zoning designation and regulations‖; (2) it ―occurs within
    city limits on a project site of no more than five acres substantially surrounded by
    urban uses‖; (3) its ―site has no value[] as habitat for endangered, rare or
    3
    threatened species‖ and ―can be adequately served by all required utilities and
    public services‖; and (4) its approval ―would not result in any significant effects
    relating to traffic, noise, air quality, or water quality.‖ (Guidelines, § 15332.) The
    Board also found that Guidelines section 15300.2, subdivision (c), does not
    preclude use of these categorical exemptions because the project as proposed and
    approved will not have any significant effects on the environment due to unusual
    circumstances.
    Several residents of the City, including appellant Susan Nunes Fadley, filed
    an appeal with the city council, arguing in part that CEQA‘s categorical
    exemptions do not apply because the proposed project‘s ―unusual size, location,
    nature and scope will have significant environmental impact on its surroundings.‖
    They asserted that the proposed residence would be ―one of the largest houses in
    Berkeley, four times the average house size in its vicinity, and situated in a canyon
    where the existing houses are of a much smaller scale.‖ They submitted evidence
    that, of Berkeley‘s over 17,000 single-family residences, only 17 exceed 6,000
    square feet, only 10 exceed 6,400 square feet, and only one exceeds 9,000 square
    feet. They also asserted that the proposed residence would exceed the maximum
    allowable height under Berkeley‘s municipal code and would be inconsistent with
    the policies of the City‘s general plan, and that an EIR is appropriate to evaluate
    the proposed construction‘s potential impact on noise, air quality, historic
    resources, and neighborhood safety. In response, the City‘s director of planning
    and development stated that 16 residences within 300 feet of the project have a
    greater floor-area-to-lot-area ratio and that 68 Berkeley ―dwellings‖ exceed 6,000
    square feet, nine exceed 9,000 square feet, and five exceed 10,000 square feet.
    The city council received numerous letters and e-mails regarding the
    appeal, some in support and some in opposition. Among the appeal‘s supporters
    was Lawrence Karp, an architect and geotechnical engineer. In a letter dated
    April 16, 2010, Karp stated: (1) he had reviewed the architectural plans and
    topographical survey filed with the Board, and had visited the proposed
    4
    construction site; (2) ―[p]ortions of the major fill for the project are shown to be
    placed on an existing slope inclined at about 42º (~1.1h:1v) to create a new slope
    more than 50º (~0.8h:1v)‖; (3) ―[t]hese slopes cannot be constructed by earthwork
    and all fill must be benched and keyed into the slope which is not shown in the
    sections or accounted for in the earthwork quantities. To accomplish elevations
    shown on the architectural plans, shoring and major retaining walls not shown will
    have to be constructed resulting in much larger earthwork quantities than now
    expected‖; (4) the ―massive grading‖ necessary would involve ―extensive trucking
    operations‖; (5) the work that would be necessary ―has never before been
    accomplished in the greater area of the project outside of reservoirs or construction
    on the University of California campus and Tilden Park‖; (6) the project site is
    ―located alongside the major trace of the Hayward fault and it is mapped within a
    state designated earthquake-induced landslide hazard zone‖; and (7) ―the project
    as proposed is likely to have very significant environmental impacts not only
    during construction but in service due to the probability of seismic lurching of the
    oversteepened side-hill fills.‖
    In a second letter addressing the investigation of geotechnical engineer
    Alan Kropp, Karp stated: (1) no ―fill slopes‖ were shown in Kropp‘s plan and
    ―the recommendations for retaining walls do not include lateral earth pressures for
    slopes with inclinations of more than 2h:1v (~27º) or for wall heights more than
    12 feet‖; (2) the project‘s architectural plans ―include cross-sections and elevations
    that are inconsistent with the Site Plan and limitations in‖ Kropp‘s report; (3) ―all
    vegetation will have to be removed for grading, and retaining walls totaling 27 feet
    in height will be necessary to achieve grades. Vertical cuts for grading and
    retaining walls will total about 43 feet (17 feet for bench cutting and 26 feet for
    wall cutting). [¶] A drawing in the [Kropp] report depicts site drainage to be
    collected and discharged into an energy dissipater dug into the slope, which is
    inconsistent with the intended very steep fill slopes‖; and (4) ―the project as
    proposed is likely to have very significant environmental impacts not only during
    5
    construction, but in service due to the probability of seismic lurching of the
    oversteepened side-hill fills.‖
    In response, Kropp stated that the project site is in an area where an
    investigation is required to evaluate the potential for landslides, and that he had
    conducted the necessary investigation and found there is, in fact, no landslide
    hazard. Kropp also stated that, in raising concerns about ―side-hill fill,‖ Karp had
    ―misread[]‖ the project plans. According to Kropp, ―the only fill placed by the
    downhill portion of the home will be backfill for backyard retaining walls and
    there will be no side-hill fill placed for the project. The current ground surface,
    along with the vegetation, will be maintained on the downhill portion of the lot.‖
    Because there will not, as Karp claimed, be any ―steep, side-hill fill constructed,‖
    Karp‘s concerns do not apply to the proposed construction. A civil engineer, Jim
    Toby, also submitted a letter stating that he saw ―no evidence‖ in the project plans
    that fill will be placed ― ‗directly on steep slopes‘ ‖ and that Karp‘s contrary
    assertion is based on a ―misreading‖ of the plans.
    In support of the permit approval, the City‘s director of planning and
    development submitted a supplemental report stating: ―A geotechnical report was
    prepared and signed by a licensed Geotechnical Engineer and a Certified
    Engineering Geologist. This report concluded that the site was suitable for the
    proposed dwelling from a geotechnical standpoint and that no landslide risk was
    present at the site. Should this project proceed, the design of the dwelling will
    require site-specific engineering to obtain a building permit.‖
    The city council addressed the appeal at a meeting on April 27, 2010. Karp
    was one of the speakers at the meeting. He began by stating his credentials,
    explaining that he (1) is ―a geotechnical engineer specializing in foundation
    engineering and construction‖; (2) has ―an earned doctorate degree in civil
    engineering and other degrees from U.C. Berkeley including two masters and a
    post-doctoral certificate in earthquake engineering‖; (3) is ―fully licensed‖ and had
    ―taught foundational engineering at Berkeley for 14 years and at Stanford for
    6
    three‖; (4) has ―experience‖ that ―includes over 50 years of design and
    construction in Berkeley‖; and (5) ―prepare[s] feasibility studies before, and
    engineering during, construction of unusual projects.‖ After affirming the opinion
    he had earlier stated in his letters, he offered this response to the assertion that he
    had misread the project plans: ―The recent report from [applicants] say I don‘t
    know how to read architectural drawings, but I have been a licensed architect for
    many years and I do know how. [¶] Their reports have not changed my opinion.‖
    After hearing from Karp, Kropp, and others, the city council adopted the Board‘s
    findings, affirmed the permit approval, and dismissed the appeal. The city
    planning department later filed a notice of exemption, stating that the project is
    categorically exempt from CEQA under Guidelines sections 15303, subdivision
    (a), and 15332, and that Guidelines section 15300.2 did not apply.
    Fadley then filed a petition for writ of mandate in the trial court, joined by
    appellant Berkeley Hillside Preservation, which is a self-described unincorporated
    association of ―City residents and concerned citizens who enjoy and appreciate the
    Berkeley hills and their environs and desire to protect the City‘s historic, cultural,
    architectural, and natural resources.‖ Following a hearing, the trial court denied
    the petition. It first concluded that the administrative record contains substantial
    evidence to support the City‘s application of the Class 32 in-fill and Class 3 small
    structures categorical exemptions. It next found that Guidelines section 15300.2,
    subdivision (c), did not preclude application of these categorical exemptions
    because, notwithstanding evidence of potentially significant environmental effects,
    the proposed project does not present any unusual circumstances.
    The Court of Appeal reversed. After noting appellants‘ concession, for
    purposes of appeal, that the project satisfies the requirements of the Class 3 and
    Class 32 exemptions, the Court of Appeal agreed with appellants that the unusual
    circumstances exception precludes the City from relying on those exemptions.2 In
    2      The concurring opinion prefers to call section 15300.2, subdivision (c), ―the
    significant effect exception,‖ based on its title. (Conc. opn. of Liu, J., post, at p.
    7
    the court‘s view, ―the fact that proposed activity may have an effect on the
    environment is itself an unusual circumstance‖ that triggers the exception,
    ―because such action would not fall ‗within a class of activities that does not
    normally threaten the environment,‘ and thus should be subject to further
    environmental review.‖ The court next reasoned that the standard of judicial
    review for an agency‘s determination that the exception does not apply is whether
    the record contains evidence of a fair argument of a significant effect on the
    environment, not whether substantial evidence supports the agency‘s
    determination. Finally, finding substantial evidence of a fair argument that the
    proposed project may have a significant environmental impact, the court held that
    the unusual circumstances exception renders the categorical exemptions
    inapplicable. It ordered the trial court ―to issue a writ of mandate directing the
    City to set aside the approval of use permits and its finding of a categorical
    exemption, and to order the preparation of an EIR.‖
    We then granted respondents‘ petition for review.
    II. DISCUSSION
    As they did in the Court of Appeal, appellants concede for purposes of this
    appeal that the proposed project comes within the terms of the Class 3 (small
    structures) and Class 32 (in-fill development) exemptions under the Guidelines.
    What they do not concede is that the City may rely on those exemptions. In their
    view, as the Court of Appeal held, the unusual circumstances exception precludes
    such reliance. Respondents, in challenging the Court of Appeal‘s decision, raise
    6.) Our use of the term ―unusual circumstances exception‖ is consistent with the
    Court of Appeal‘s decision in this case and the vast majority of published case
    law. Of course, a provision‘s title ―is never allowed to enlarge or control the
    language in the body of the [provision].‖ (Hagar v. Sup. of Yolo Co. (1874) 
    47 Cal. 222
    , 232; see DaFonte v. Up-Right, Inc. (1992) 
    2 Cal.4th 593
    , 602 [―Title or
    chapter headings are unofficial and do not alter the explicit scope, meaning, or
    intent of a statute.‖].)
    8
    two primary arguments: (1) a proposed project‘s potential significant effect on the
    environment is not, as the Court of Appeal held, itself an unusual circumstance
    that triggers the exception, and an unusual circumstance apart from the project‘s
    potential environmental effect is a prerequisite to the exception‘s application; and
    (2) in reviewing the City‘s conclusion that the exception is inapplicable, the Court
    of Appeal should have determined whether there was substantial evidence in the
    record to support that conclusion, not whether the record contains evidence of a
    fair argument of a significant effect on the environment. To these arguments, we
    now turn.
    A. A Potentially Significant Environmental Effect Is Not Alone
    Sufficient to Trigger the Unusual Circumstances Exception.
    Generally, the rules that govern interpretation of statutes also govern
    interpretation of administrative regulations. (Guzman v. County of Monterey
    (2009) 
    46 Cal.4th 887
    , 898; Cal. Drive-in Restaurant Assn. v. Clark (1943) 
    22 Cal.2d 287
    , 292.) Thus, we begin here with the language of the unusual
    circumstances exception, giving effect to its usual meaning and avoiding
    interpretations that render any language surplusage. (Brewer v. Patel (1993) 
    20 Cal.App.4th 1017
    , 1021.) As noted earlier, Guidelines section 15300.2,
    subdivision (c), provides: ―A categorical exemption shall not be used for an
    activity where there is a reasonable possibility that the activity will have a
    significant effect on the environment due to unusual circumstances.‖ The plain
    language of this provision supports the view that, for the exception to apply, it is
    not alone enough that there is a reasonable possibility the project will have a
    significant environmental effect; instead, in the words of the Guideline, there must
    be ―a reasonable possibility that the activity will have a significant effect on the
    environment due to unusual circumstances.‖ (Guidelines, § 15300.2, subd. (c),
    italics added.)
    9
    Contrary to our rules for interpreting regulations, appellants‘ proposed
    construction, which mirrors that of the Court of Appeal and which the concurring
    opinion would adopt, would give no meaning to the phrase ―due to unusual
    circumstances.‖ According to appellants, this phrase is merely ―descriptive‖ in
    that ―[u]nusual circumstances‖ are simply ―self-evident underpinnings‖ when a
    project that otherwise satisfies the requirements of a categorical exemption
    nevertheless ―has potentially significant impacts.‖ Likewise, the concurring
    opinion asserts that ―the phrase ‗unusual circumstances‘ . . . simply describes the
    nature of a project that, while belonging to a class of projects that typically have
    no significant environmental effects, nonetheless will have such effects.‖ (Conc.
    opn, post, at p. 2.) In other words, in the view of appellants and the concurring
    opinion, the phrase ―due to unusual circumstances‖ adds nothing to the meaning of
    the regulation, and the exception applies if there is a fair argument that a project
    ―may‖ (according to appellants) or ―will‖ (according to the concurring opinion
    (ibid.)) have a significant environmental effect. However, had that been the
    Secretary‘s intent, the phrase ―due to unusual circumstances‖ would, no doubt,
    have been omitted from the regulation; rather than confuse the issue with
    meaningless language, the regulation would clearly and simply provide that the
    exception applies ―if there is a reasonable possibility that the activity will have a
    significant effect on the environment.‖ Reading the phrase ―due to unusual
    circumstances‖ out of the regulation, as appellants and the concurring opinion
    propose, would be contrary to the principle of construction that directs us ―to
    accord meaning to every word and phrase in a regulation.‖ (Price v. Starbucks
    Corp. (2011) 
    192 Cal.App.4th 1136
    , 1145.)
    In addition, we agree with respondents that, under the construction of
    appellants and the concurring opinion, the categorical exemptions the Legislature,
    through the Secretary, has established would have little, if any, effect. CEQA
    10
    specifies that environmental review through preparation of an EIR is required only
    ―[i]f there is substantial evidence . . . that the project may have a significant effect
    on the environment.‖ (§ 21080, subd. (d).) As a corollary to this principle, CEQA
    also specifies that, if ―[t]here is no substantial evidence, in light of the whole
    record before the lead agency, that the project may have a significant effect on the
    environment,‖ then the proposed project is not subject to further CEQA review.
    (§ 21080, subd. (c)(1).) Guidelines section 15061, subdivision (b)(3), captures
    these principles by specifying: ―Where it can be seen with certainty that there is
    no possibility that the activity in question may have a significant effect on the
    environment, the activity is not subject to CEQA.‖
    Under these provisions, where there is no substantial evidence a proposed
    project may have a significant environmental effect, further CEQA review is
    unnecessary; no categorical exemption is necessary to establish that proposition.
    According to appellants, under the unusual circumstances exception, the
    categorical exemptions are inapplicable unless an agency ―check[s] its files‖ and
    finds no ―evidence of potentially significant impacts.‖ But this is precisely the
    inquiry an agency makes under Guidelines section 15061, subdivision (b)(3), to
    determine whether the proposed project is subject to CEQA review in the first
    instance. (Muzzy Ranch Co. v. Solano County Airport Land Use Com. (2007) 
    41 Cal.4th 372
    , 387 (Muzzy Ranch) [under Guidelines, § 15061, subd. (b)(3), agency
    must determine whether the evidence in the administrative record shows no
    possibility the proposed activity may have a significant effect on the
    environment].) And appellants‘ test for determining whether the unusual
    circumstances exception applies —whether there is a ―reasonable possibility‖ the
    proposed project ―will have a significant effect on the environment‖ (Guidelines, §
    15300.2, subd. (c)) — is precisely the test used to determine whether Guidelines
    section 15061, subdivision (b)(3), applies. (California Farm Bureau Federation v.
    11
    California Wildlife Conservation Bd. (2006) 
    143 Cal.App.4th 173
    , 194
    [Guidelines, § 15061, subd. (b)(3), inapplicable if ―there is a reasonable possibility
    that a proposed project will have a significant effect upon the environment‖].)
    Thus, under appellants‘ view, the categorical exemptions would serve no purpose;
    they would apply only when the proposed project is, by statute and Guidelines
    section 15061, subdivision (b)(3), already outside of CEQA review.
    Appellants assert that applying a categorical exemption despite a proposed
    project‘s potential significant environmental effect would contravene CEQA
    statutes and the Legislature‘s intent in passing CEQA. They rely on three CEQA
    provisions: (1) section 21100, subdivision (a), which directs preparation of an EIR
    ―on any project . . . that may have a significant effect on the environment‖; (2)
    section 21151, which similarly directs preparation of an EIR ―on any project . . .
    which may have a significant effect on the environment‖; and (3) section 21082.2,
    subdivision (d), which states that an EIR ―shall‖ be prepared ―[i]f there is
    substantial evidence, in light of the whole record before the lead agency, that a
    project may have a significant effect on the environment.‖ This statutory
    authority, appellants assert, ―does not allow categorical exemptions for any project
    that may have a significant effect on the environment.‖ In other words, ―the
    documented presence of a potential environmental effect . . . always defeat[s] a
    categorical exemption.‖ ―[T]he statutory authority [the Legislature] has given to
    the Secretary only allows categorical exemption for projects that have no
    significant environmental effect, and ‗no statutory policy exists in favor of
    applying categorical exemptions where a fair argument can be made that a project
    will create a significant effect on the environment.‘ ‖ Thus, appellants assert,
    requiring more than a showing that a proposed project may have a significant
    effect in the environment ―would be inconsistent with‖ CEQA‘s statutory
    ―mandates.‖
    12
    Appellants‘ argument ignores a basic principle of statutory interpretation:
    courts ―do not construe statutes in isolation, but rather read every statute ‗with
    reference to the entire scheme of law of which it is part so that the whole may be
    harmonized and retain effectiveness.‘ ‖ (People v. Pieters (1991) 
    52 Cal.3d 894
    ,
    899.) Thus, we must consider the three sections appellants cite, not in isolation,
    but ― ‗in the context of the statutory framework as a whole‘ ‖ in order to
    harmonize CEQA‘s ― ‗various parts.‘ ‖ (Palos Verdes Faculty Assn. v. Palos
    Verdes Peninsula Unified Sch. Dist. (1978) 
    21 Cal.3d 650
    , 659 [construing the Ed.
    Code].)
    Here, several CEQA provisions, as well as their evolution, are relevant to
    the issue. When the Legislature enacted CEQA in 1970, it directed the Governor‘s
    Office of Planning and Research (OPR), ―in conjunction with appropriate state,
    regional, and local agencies,‖ to ―coordinate the development of objectives,
    criteria, and procedures to assure the orderly preparation and evaluation of‖ EIRs.
    (Former § 21103, added by Stats. 1970, ch. 1433, § 1, pp. 2780, 2782.) Two years
    later, in Friends of Mammoth v. Board of Supervisors (1972) 
    8 Cal.3d 247
    , 259
    (Mammoth), we held that CEQA applies, not just to public projects, but also to
    private activities requiring a government permit or similar entitlement. Before
    Mammoth, it had been ―generally believed‖ that CEQA ―appl[ied] only to projects
    undertaken or funded by public agencies.‖ (Friends of Lake Arrowhead v. Board
    of Supervisors (1974) 
    38 Cal.App.3d 497
    , 513.) Cognizant of our decision‘s
    potential ramifications, after recognizing that ―the reach of the statutory phrase,
    ‗significant effect on the environment,‘ is not immediately clear,‖ we noted: ―To
    some extent this is inevitable in a statute which deals, as the [CEQA] must, with
    questions of degree. Further legislative or administrative guidance may be
    forthcoming on this point among others.‖ (Mammoth, supra, at p. 271, italics
    added.) We then added: ―[C]ommon sense tells us that the majority of private
    13
    projects for which a government permit or similar entitlement is necessary are
    minor in scope — e.g., relating only to the construction, improvement, or
    operation of an individual dwelling or small business — and hence, in the absence
    of unusual circumstances, have little or no effect on the public environment. Such
    projects, accordingly, may be approved exactly as before the enactment of the
    [CEQA].‖ (Id. at p. 272.)
    The Legislature immediately responded to Mammoth by amending CEQA
    through urgency legislation. (See County of Inyo v. Yorty (1973) 
    32 Cal.App.3d 795
    , 803.) As relevant here, it added section 21083, which generally directed the
    OPR, ―as soon as possible,‖ to ―prepare and develop proposed guidelines for the
    implementation of [CEQA],‖ and directed the Secretary to ―certify and adopt the
    [OPR‘s proposed] guidelines pursuant to‖ the Administrative Procedure Act.
    (Stats. 1972, ch. 1154, § 1, pp. 2271, 2272-2273.) These directives exist today as
    subdivisions (a) and (e) of section 21083. More specifically, in several provisions,
    the Legislature provided for categorical exemptions to CEQA. In section 21084, it
    provided: ―The guidelines prepared and adopted pursuant to Section 21083 shall
    include a list of classes of projects which have been determined not to have a
    significant effect on the environment and which shall be exempt from the
    provisions of [CEQA]. In adopting the guidelines, the Secretary . . . shall make a
    finding that the list or classification of projects referred to in this section do not
    have a significant effect on the environment.‖ (§ 21084, as added by Stats. 1972,
    ch. 1154, § 1, pp. 2271, 2273.) This provision remains substantively the same
    today. In former section 21085, the Legislature provided that ―[a]ll classes of
    projects designated pursuant to Section 21084 . . . shall be exempt from the
    provisions of [CEQA].‖ (Stats. 1972, ch. 1154, § 1, pp. 2271, 2273.) The
    substance of this section appears today in section 21080, subdivision (b)(9), which
    provides that CEQA ―does not apply‖ to ―[a]ll classes of projects designated
    14
    pursuant to Section 21084.‖ Finally, the Legislature enacted section 21086 to
    establish a mechanism for challenging the Secretary‘s categorical exemptions.
    (Stats. 1972, ch. 1154, § 1, pp. 2271, 2273-2274.) Subdivision (a) of that section
    provides: ―A public agency may, at any time, request the addition or deletion of a
    class of projects, to the list designated pursuant to Section 21084. That request
    shall be made in writing to the [OPR] and shall include information supporting the
    public agency‘s position that the class of projects does, or does not, have a
    significant effect on the environment.‖ Subdivision (b) of section 21086 requires
    the OPR to ―review each request‖ and ―submit‖ a recommendation to the
    Secretary, and authorizes the Secretary, ―[f]ollowing the receipt of [the OPR‘s]
    recommendation,‖ to ―add or delete the class of projects to the list of classes of
    projects designated pursuant to Section 21084 that are exempt from the
    requirements of [CEQA].‖ Subdivision (c) of section 21086 then provides: ―The
    addition or deletion of a class of projects, as provided in this section, to the list
    specified in Section 21084 shall constitute an amendment to the guidelines
    adopted pursuant to Section 21083 and shall be adopted in the manner prescribed
    in Sections 21083 and 21084.‖
    Collectively, these provisions indicate that the Legislature intended to
    establish by statute ―classes of projects‖ that ―have been determined not to have a
    significant effect on the environment,‖ to require the OPR and the Secretary to
    apply their expertise and identify those ―classes‖ by ―mak[ing] a finding‖ that the
    projects they comprise ―do not have a significant effect on the environment,‖ and
    to ―exempt‖ from CEQA proposed projects within the classes the OPR and the
    Secretary have identified. (§ 21084, subd. (a).) This conclusion comports with
    the impetus for the Legislature‘s enactment of these provisions: our decision in
    Mammoth, which (1) observed that CEQA‘s applicability turns on ―questions of
    degree,‖ (2) stated that ―the majority‖ of private projects ―may be approved
    15
    exactly as before‖ CEQA‘s enactment because they ―are minor in scope . . . and
    hence, in the absence of unusual circumstances, have little or no effect on the
    public environment,‖ and (3) called for ―[f]urther legislative or administrative
    guidance‖ on these issues. (Mammoth, supra, 8 Cal.3d at pp. 271-272.) To
    address these considerations, the Legislature, through the Guidelines, intended to
    enumerate classes of projects that are exempt from CEQA because,
    notwithstanding their potential effect on the environment, they already ―have been
    determined not to have a significant effect on the environment.‖ (§ 21084.) The
    Guidelines implement this intent, by setting forth the ―classes of projects‖ that the
    Secretary, acting ―[i]n response to [the Legislature‘s] mandate,‖ ―has found . . . do
    not have a significant effect on the environment.‖ (Guidelines, § 15300.) Thus,
    construing the unusual circumstances exception as requiring more than a showing
    of a fair argument that the proposed activity may have a significant environmental
    effect is fully consistent with the Legislature‘s intent.
    By contrast, as earlier explained, appellants‘ construction of the unusual
    circumstances exception would render useless and unnecessary the statutes the
    Legislature passed to identify and make exempt classes of projects that have no
    significant environmental effect. Try as they might, appellants can identify no
    purpose or effect of the categorical exemption statutes if, as they assert, a showing
    of a fair argument of a potential environmental effect precludes application of all
    categorical exemptions. Construing the unusual circumstances exception to apply
    any time there is a reasonable possibility of a significant environmental effect
    would, therefore, contravene our duty to adopt a construction that gives effect to
    all parts of the statutory and regulatory framework, rather than one that renders
    part of the framework ―wholly useless and unnecessary.‖ (French Bank Case
    (1879) 
    53 Cal. 495
    , 530.)
    16
    The concurring opinion‘s attempt to succeed where appellants have
    failed — i.e., to show that the categorical exemptions still have some ―value‖
    under their construction (conc. opn, post, at p. 9) — is also unpersuasive. The
    concurring opinion first asserts that proposed projects enjoy ―a considerable
    procedural advantage‖ when an agency finds that they fall within the terms of an
    exempt category. (Conc. opn., post, at p. 10.) As to such projects, the concurring
    opinion notes, an agency need not follow any particular procedure, include any
    written determination, undertake an initial study, or adopt a negative declaration.
    (Ibid.) However, the same is true of proposed projects that fall within the terms of
    Guidelines section 15061, subdivision (b)(3), i.e., projects that are ―not subject to
    CEQA‖ because ―it can be seen with certainty that there is no possibility that
    [they] may have a significant effect on the environment.‖ (See Muzzy Ranch,
    
    supra,
     41 Cal.4th at p. 380 [initial study not required where Guidelines, § 15061,
    subd. (b)(3) applies].) As already explained, the concurring opinion‘s
    interpretation renders the categorical exemptions duplicative of this guideline, and
    the concurring opinion does not persuasively demonstrate otherwise. Thus, its
    discussion of these so-called procedural advantages fails to show that, under its
    interpretation, the categorical exemptions have independent value.
    The concurring opinion also notes that, when an agency finds that a project
    meets the terms of a categorical exemption, it ―impliedly finds that it has no
    significant impact,‖ and ―the burden shifts to‖ project opponents ―to produce
    evidence‖ that the unusual circumstances exception applies. (Conc. opn, post, at
    pp. 9-10.) This is significant, the concurring opinion maintains, because ―[i]n
    many cases, categorical exemptions are not litigated, and the applicability of the
    exemption is evident.‖ (Id. at p. 10.)
    However, even if a proposed project faces no opposition, an agency
    invoking a categorical exemption may not simply ignore the unusual
    17
    circumstances exception; it must ―consider the issue of significant effects . . . in
    determining whether the project is exempt from CEQA where there is some
    information or evidence in the record that the project might have a significant
    environmental effect.‖ (Association for Protection etc. Values v. City of Ukiah
    (1991) 
    2 Cal.App.4th 720
    , 732 (Ukiah).) This follows from Guidelines section
    15061, subdivisions (a) and (b)(2), which, respectively, (1) direct a lead agency to
    determine whether a proposed project is ―exempt from CEQA,‖ and (2) specify
    that a project is exempt if a categorical exemption applies ―and the application of
    that categorical exemption is not barred by one of the exceptions set forth in
    Section 15300.2.‖ Thus, an agency may not apply a categorical exemption
    without considering evidence in its files of potentially significant effects,
    regardless of whether that evidence comes from its own investigation, the
    proponent‘s submissions, a project opponent, or some other source. Moreover,
    under the concurring opinion‘s interpretation, if those files contain ―substantial
    evidence‖ of a mere ―fair argument‖ that the project will have significant
    environmental effects, the agency may not apply a categorical exemption. (Conc.
    opn, post, at p. 14.) Thus, under the concurring opinion‘s interpretation of the
    unusual circumstances exception, the ―considerable procedural advantage‖ the
    concurring opinion posits is largely illusory. (Id. at p. 10.)
    Also illusory is the ―second advantage‖ that, in the view of the concurring
    opinion, gives some value to categorical exemptions under its interpretation: the
    ―comparative arguments‖ available to project proponents when an opponent
    invokes the unusual circumstances exception. (Conc. opn, post, at p. 11.)
    According to the concurring opinion, proponents may ―argue,‖ if ―supported by
    evidence,‖ that (1) the project‘s effects are ―typical‖ of those generated by projects
    in the exempt category, ―such that few or no projects in the category would be
    exempt if the effects were deemed significant,‖ and (2) ―the project‘s dimensions
    18
    or features are not unusual compared to typical projects in the exempt category,
    thereby suggesting that the project is similar to those that the Secretary has
    determined not to have a significant environmental effect.‖ (Id. at pp. 11-12.)
    However, under the fair argument test the concurring opinion would apply here,
    ―an agency is merely supposed to look to see if the record shows substantial
    evidence of a fair argument that there may be a significant effect. [Citations.] In
    other words, the agency is not to weigh the evidence to come to its own conclusion
    about whether there will be a significant effect. It is merely supposed to inquire,
    as a matter of law, whether the record reveals a fair argument. . . . ‗ ―[I]t does not
    resolve conflicts in the evidence but determines only whether substantial evidence
    exists in the record to support the prescribed fair argument.‖ ‘ [Citation.] ‖
    (Banker’s Hill, Hillcrest, Park West Community Preservation Group v. City of San
    Diego (2006) 
    139 Cal.App.4th 249
    , 263 (Banker’s Hill); see Guidelines, § 15064,
    subd. (f)(1) [a lead agency ―presented with a fair argument that a project may have
    a significant effect on the environment . . . shall prepare an EIR even though it
    may also be presented with other substantial evidence that the project will not
    have a significant effect‖].) Thus, under the concurring opinion‘s interpretation,
    evidence a project proponent offers to show that the project will only have typical
    effects, dimensions, and features is irrelevant if a project opponent can make a
    mere fair argument that those effects, dimensions, or features are not typical, or
    that the project will have a significant environmental effect. For these reasons, the
    concurring opinion fails to demonstrate that the categorical exemptions would
    retain any significant ―value‖ under its interpretation. (Conc. opn, post, at p. 9.)
    Moreover, contrary to the assertion of the concurring opinion, even were
    the categorical exemptions to retain some limited value under its construction,
    there would still be ―reason[s]‖ (conc. opn, post, at p. 14) to reject that
    construction. First, as earlier explained (ante, p. 10), because that construction
    19
    would transform the phrase ―due to unusual circumstances‖ into meaningless
    surplusage, it is one we ―should avoid.‖ (Metcalf v. County of San Joaquin (2008)
    
    42 Cal.4th 1121
    , 1135.) Second, nothing suggests that either the Legislature or the
    Secretary intended the categorical exemptions to have such minuscule value. Had
    that been their intent, surely they would have expressed it in a more clear, concise,
    direct, and obvious way.
    Accordingly, the Court of Appeal erred by holding that a potentially
    significant environmental effect itself constitutes an unusual circumstance. In
    listing a class of projects as exempt, the Secretary has determined that the
    environmental changes typically associated with projects in that class are not
    significant effects within the meaning of CEQA, even though an argument might
    be made that they are potentially significant. The plain language of Guidelines
    section 15300.2, subdivision (c), requires that a potentially significant effect must
    be ―due to unusual circumstances‖ for the exception to apply. The requirement of
    unusual circumstances recognizes and gives effect to the Secretary‘s general
    finding that projects in the exempt class typically do not have significant impacts.
    As to projects that meet the requirements of a categorical exemption, a
    party challenging the exemption has the burden of producing evidence supporting
    an exception. (Davidon Homes v. City of San Jose (1997) 
    54 Cal.App.4th 106
    ,
    115; see 1 Kostka & Zischke, Practice under the Cal. Environmental Quality Act
    (2d ed. 2008) § 5.71 (citing cases).) As explained above, to establish the unusual
    circumstances exception, it is not enough for a challenger merely to provide
    substantial evidence that the project may have a significant effect on the
    environment, because that is the inquiry CEQA requires absent an exemption.
    (§ 21151.) Such a showing is inadequate to overcome the Secretary‘s
    determination that the typical effects of a project within an exempt class are not
    significant for CEQA purposes. On the other hand, evidence that the project will
    20
    have a significant effect does tend to prove that some circumstance of the project
    is unusual. An agency presented with such evidence must determine, based on the
    entire record before it — including contrary evidence regarding significant
    environmental effects — whether there is an unusual circumstance that justifies
    removing the project from the exempt class.
    This reading of the guideline is not inconsistent with the phrase ―reasonable
    possibility that the activity will have a significant effect on the environment.‖
    (Guidelines, § 15300.2, subd. (c).) A party invoking the exception may establish
    an unusual circumstance without evidence of an environmental effect, by showing
    that the project has some feature that distinguishes it from others in the exempt
    class, such as its size or location. In such a case, to render the exception
    applicable, the party need only show a reasonable possibility of a significant effect
    due to that unusual circumstance. Alternatively, under our reading of the
    guideline, a party may establish an unusual circumstance with evidence that the
    project will have a significant environmental effect. That evidence, if convincing,
    necessarily also establishes ―a reasonable possibility that the activity will have a
    significant effect on the environment due to unusual circumstances.‖ (Guidelines,
    § 15300.2, subd. (c).)
    As this discussion demonstrates, our approach is consistent with the
    concurring opinion‘s statement of its central proposition: ―When it is shown that a
    project otherwise covered by a categorical exemption will have a significant
    environmental effect, it necessarily follows that the project presents unusual
    circumstances.‖ (Conc. opn, post, at p. 2, italics added.) However, for reasons
    already set forth, we part company with the concurring opinion when it moves
    from this central proposition to the conclusion that a reviewing court must find the
    exception applicable, and overturn an agency‘s application of an exemption, if
    there is ―substantial evidence‖ of ―a fair argument that the project will have
    21
    significant environmental effects.‖ (Ibid.) The Secretary, in complying with the
    Legislature‘s command to determine the ―classes of projects‖ that ―do not have a
    significant effect on the environment‖ (§ 21084, subd. (a)), necessarily resolved
    any number of ―fair arguments‖ as to the possible environmental effects of
    projects in those classes. Allowing project opponents to negate those
    determinations based on nothing more than ―a fair argument that the project will
    have significant environmental effects‖ (conc. opn., post, at p. 12) would be
    fundamentally inconsistent with the Legislature‘s intent in establishing the
    categorical exemptions.
    Appellants assert that Wildlife Alive v. Chickering (1976) 
    18 Cal.3d 190
    (Chickering) precludes us from construing the unusual circumstances exception to
    require a showing of something more than a potentially significant environmental
    effect. There, we held in relevant part that the setting of hunting and fishing
    seasons by the Fish and Game Commission (Commission) was not exempt from
    CEQA under Guidelines former section 15107. (Chickering, supra, at p. 205.)
    That former guideline established a categorical exemption for ― ‗actions taken by
    regulatory agencies . . . to assure the maintenance, restoration, or enhancement of
    a natural resource where the regulatory process involves procedures for protection
    of the environment‘ ‖ (id. at p. 204), and it described as an example ― ‗the wildlife
    preservation activities of the State Department of Fish and Game.‘ ‖ (Id. at p.
    205.) We gave two reasons for finding this exemption inapplicable on its terms.
    First, the Commission ―is not‖ the Department of Fish and Game. (Ibid.) Second,
    and ―[m]ore significantly,‖ several of the statutes that granted powers and duties to
    the Department of Fish and Game ―contemplate projects specifically designed for
    the preservation of wildlife.‖ (Ibid.) These are the ―departmental functions‖ to
    which the former guideline referred in mentioning ―[t]he ‗wildlife preservation
    activities of the State Department of Fish and Game.‘ ‖ (Ibid.) ―The
    22
    [Commission‘s] fixing of hunting seasons, while doubtless having an indirect
    beneficial effect on the continuing survival of certain species, cannot fairly or
    readily be characterized as a preservation activity in a strict sense.‖ (Ibid.)
    After concluding in Chickering that the Commission‘s activity did not fall
    within the language of the former guideline, we discussed why it would have been
    problematic to ―expand[]‖ that ―language to imply‖ an exemption for that activity.
    (Chickering, supra, 18 Cal.3d at p. 206.) Doing so, we stated, would contravene
    the ―principle‖ that ―CEQA must be interpreted so as to afford the ‗fullest possible
    protection‘ to the environment.‖ (Ibid.) Moreover, we explained in a passage
    appellants quote, ―if‖ we ―expand[ed]‖ (id. at p. 206) the former guideline‘s
    language ―to cover the commission‘s hunting program, it is doubtful that such a
    categorical exemption [would be] authorized under the statute. . . . [N]o regulation
    is valid if its issuance exceeds the scope of the enabling statute. [Citations.] The
    secretary is empowered to exempt only those activities which do not have a
    significant effect on the environment. (Pub. Resources Code, § 21084.) It follows
    that where there is any reasonable possibility that a project or activity may have a
    significant effect on the environment, an exemption would be improper,‖ and ―the
    setting of hunting and fishing seasons has the potential for a significant
    environmental impact . . . .‖ (Id. at pp. 205-206.)
    For several reasons, appellants‘ reliance on Chickering is unavailing. First,
    Chickering predated the Secretary‘s adoption of the unusual circumstances
    exception and, thus, addressed neither the meaning nor the validity of that
    exception. Second, as here relevant, the only issue in Chickering was whether the
    Commission‘s activity fell within the scope of Guidelines former section 15107l.
    After concluding it did not, we added the discussion appellants cite, which, to
    buttress our conclusion, explored the validity of a hypothetical exemption that
    would include the Commission‘s activity. (Chickering, supra, 18 Cal.3d at pp.
    23
    205-206.) Third, because that added discussion was tangential to the issue before
    us and unnecessary to resolve the case, it was, understandably, summary. For
    example, it did not consider the broader statutory framework, the evolution of the
    CEQA statutes, or the implications of its statement for the effectiveness of various
    other CEQA statutes. Finally, in 1993, after we decided Chickering, the
    Legislature enacted section 21083.1, which directs courts ―not [to] interpret [the
    CEQA statutes] or the state guidelines adopted pursuant to Section 21083 in a
    manner which imposes procedural or substantive requirements beyond those
    explicitly stated in [CEQA] or in the state guidelines.‖ (§ 21083.1, italics added.)
    According to the legislative history, the purpose of this statute was to ―limit
    judicial expansion of CEQA requirements‖ and to ― ‗reduce the uncertainty and
    litigation risks facing local governments and project applicants by providing a
    ―safe harbor‖ to local entities and developers who comply with the explicit
    requirements of the law.‘ ‖ (Assem. Com. on Natural Resources, Analysis of Sen.
    Bill No. 722 (1993-1994 Reg. Sess.) for hearing on July 12, 1993, p. 2.) Given
    appellants‘ concession for purposes of appeal that the proposed project here falls
    within two of the categorical exemptions, under Guidelines section 15300.2,
    subdivision (c), environmental review is necessary only if ―there is a reasonable
    possibility [the project] will have a significant effect on the environment due to
    unusual circumstances.‖ Given that the listing of a class of projects as exempt
    constitutes the Secretary‘s finding, pursuant to the Legislature‘s command, that the
    typical effects of projects within that class are not significant within the meaning
    of CEQA, interpreting the unusual circumstances exception to require
    environmental review absent unusual circumstances would violate the
    Legislature‘s express directive in section 21083.1 ―not [to] interpret‖ the CEQA
    statutes and the Guidelines ―in a manner which imposes procedural or substantive
    requirements beyond those‖ the statutes and the Guidelines ―explicitly state[].‖
    24
    As we have explained, ―in the . . . years since CEQA was enacted the
    Legislature has, for reasons of policy, expressly exempted several categories of
    projects from environmental review. (See § 21080, subd. (b)(1)-[(15)].) This
    court does not sit in review of the Legislature‘s wisdom in balancing these policies
    against the goal of environmental protection because, no matter how important its
    original purpose, CEQA remains a legislative act, subject to legislative limitation
    and legislative amendment.‖ (Napa Valley Wine Train, Inc. v. Public Utilities
    Com. (1990) 
    50 Cal.3d 370
    , 376.) Consistent with section 21083.1‘s directive, we
    have held that ―rules regulating the protection of the environment must not be
    subverted into an instrument for the oppression and delay of social, economic, or
    recreational development and advancement.‖ (Citizens of Goleta Valley v. Board
    of Supervisors (1990) 
    52 Cal.3d 553
    , 576.) Adopting appellants‘ interpretation
    would do precisely that, by requiring environmental review of projects that one
    could argue may have a significant environmental effect, but that the OPR and the
    Secretary, exercising the authority the Legislature has by statute delegated to them
    and required them to exercise, have already determined do not, in fact, ―have a
    significant effect on the environment.‖ (§ 21084, subd. (a).)
    Appellants also substantially rely on this court‘s decision in Mountain Lion
    Foundation v. Fish and Game Commission (1997) 
    16 Cal.4th 105
     (Mountain
    Lion). There, the majority held in relevant part that the same categorical
    exemption previously at issue in Wildlife Alive — which had been renumbered as
    Guidelines section 15307 — did not apply to the Commission‘s decision to
    remove the Mojave ground squirrel from the threatened species list. (Mountain
    Lion, supra, at pp. 124-127.) As noted earlier, that guideline establishes an
    exemption for ―actions taken by regulatory agencies as authorized by state law or
    local ordinance to assure the maintenance, restoration, or enhancement of a natural
    resource where the regulatory process involves procedures for protection of the
    25
    environment.‖ (Guidelines, § 15307.) The majority found that ―a delisting action
    cannot be fairly included within this class‖ because it ―removes rather than secures
    [the] protections‖ that an endangered or threatened species enjoys under the
    California Endangered Species Act. (Mountain Lion, 
    supra, at p. 125
    .) Moreover,
    the majority added, in light of other Guidelines, a delisting could not come within
    a categorical exemption. ―[A] categorical exemption represents a determination
    by the Secretary that a particular project does not have a significant effect on the
    environment. (§ 21084.)‖ (Mountain Lion, 
    supra, at 124
    .) ―It follows,‖ the
    majority stated in the passage on which appellants rely, ―that an activity that may
    have a significant effect on the environment cannot be categorically exempt.‖
    (Ibid.) Under Guidelines section 15065, subdivision (a), an agency ―must find‖
    that a proposed project may have that effect if it has ― ‗the potential to . . . reduce
    the . . . number or restrict the range of an endangered, rare or threatened species.‘ ‖
    (Mountain Lion, supra, at p. 124.) Because a delisting, by ―withdraw[ing] existing
    levels of protection,‖ ―creates at least the potential for population reduction or
    habitat restriction,‖ this guideline ―obligate[s]‖ the Commission ―to find a
    delisting may have a significant environmental effect. Such a finding precludes
    invocation of a categorical exemption.‖ (Ibid.)
    For reasons similar to those earlier discussed in connection with
    Chickering, supra, 
    18 Cal.3d 190
    , appellants‘ reliance on Mountain Lion is
    unavailing. Like Chickering, Mountain Lion addressed neither the meaning nor
    the validity of the unusual circumstances exception. Also like Chickering, as here
    relevant, Mountain Lion presented only the issue of whether the Commission‘s
    activity fell within the express terms of a categorical exemption. Because the
    court found it did not, the hypothetical discussion of whether the Secretary could
    have established a categorical exemption was tangential, unnecessary, and
    summary. In any event, properly understood, the discussion in Mountain Lion
    26
    stands only for the proposition that the Secretary, having established in one
    guideline that a delisting may have a significant effect on the environment, may
    not in another guideline ―make a finding‖ that delistings, as a class, ―do not have a
    significant effect on the environment‖ and are therefore exempt from CEQA.
    (§ 21084.) It does not, as appellants assert, establish that where the Secretary,
    exercising statutorily delegated authority, has found that projects of a certain kind
    ―do not have a significant effect on the environment‖ and are exempt from CEQA,
    a proposed project that falls within that class and does not involve any unusual
    circumstances is, nonetheless, subject to environmental review if an argument can
    be made that it may have a significant effect on the environment. That question
    simply was not before us in Mountain Lion, supra, 
    16 Cal.4th 105
    .3
    B. Standards of Review.
    Several CEQA statutes expressly address judicial review of agency action.
    Section 21168 provides the standard of review for decisions ―made as a result of a
    proceeding in which by law a hearing is required to be given, evidence is required
    to be taken and discretion in the determination of facts is vested in a public
    agency.‖ Section 21168.5 provides the standard of review in all other actions ―to
    attack, review, set aside, void or annul a determination, finding, or decision of a
    public agency on the grounds of noncompliance with [CEQA].‖ Because nothing
    required the City to hold an evidentiary hearing in this case, the latter section
    governs. Under it, a court‘s inquiry is ―whether there was a prejudicial abuse of
    discretion. Abuse of discretion is established if the agency has not proceeded in a
    manner required by law or if the determination or decision is not supported by
    3      Consistent with the preceding analysis, we disapprove Communities for a
    Better Environment v. California Resources Agency (2002) 
    103 Cal.App.4th 98
    ,
    129, insofar as it suggests that a proposed project‘s potential environmental effects
    alone render the unusual circumstances exception applicable.
    27
    substantial evidence.‖ (Ibid.) Thus, reversal of the City‘s action here is
    appropriate only if (a) the City, in finding the proposed project categorically
    exempt, did not proceed in the manner required by law, or (b) substantial evidence
    fails to support that finding.4
    The parties disagree about how these standards apply to an agency‘s
    determination that the unusual circumstances exception is inapplicable.
    Respondents, invoking the traditional substantial evidence standard, argue that a
    reviewing court must uphold such a determination if substantial evidence supports
    it, even if substantial evidence in the record also shows that a contrary conclusion
    would be equally, or even more, reasonable. Appellants, on the other hand,
    contend that, even if substantial evidence supports the agency‘s determination, a
    reviewing court must overturn the determination if there is a fair argument based
    on substantial evidence that the proposed project may have a significant effect on
    the environment due to unusual circumstances. A fair argument exists, appellants
    assert, ―if any facts, fact-based assumptions, or expert opinion in the
    administrative record support . . . arguments that [the] exception may apply,
    regardless of contrary evidence.‖
    The fair argument approach derives from our application of section 21168.5
    in No Oil, Inc. v. City of Los Angeles (1974) 
    13 Cal.3d 68
     (No Oil). There, we
    4       We have previously observed that ―the standard of review is essentially the
    same‖ under sections 21168 and 21168.5. (Laurel Heights Improvement Assn. v.
    Regents of University of California (1993) 
    6 Cal.4th 1112
    , 1133, fn. 17 (Laurel
    Heights II).) Section 21168 requires review ―in accordance with the provisions of
    Section 1094.5 of the Code of Civil Procedure,‖ and declares that ―the court shall
    not exercise its independent judgment on the evidence but shall only determine
    whether the act or decision is supported by substantial evidence in the light of the
    whole record.‖ Code of Civil Procedure section 1094.5, subdivision (b), provides,
    similarly to section 21168.5, that ―[a]buse of discretion is established if the
    respondent has not proceeded in the manner required by law, the order or decision
    is not supported by the findings, or the findings are not supported by the
    evidence.‖
    28
    reviewed the City of Los Angeles‘s application of section 21151, which requires
    preparation of an EIR for a nonexempt project that ―may have a significant effect
    on the environment.‖ Although the proposed project in No Oil did not qualify for
    an exemption under the CEQA statutes or the Guidelines, Los Angeles had found,
    after conducting an initial threshold environmental study, that no EIR was
    necessary because the project would not have a significant effect on the
    environment. We reversed, concluding that the finding constituted a prejudicial
    abuse of discretion under section 21168.5 because, in making it, Los Angeles had
    failed to proceed as required by law in two ways: (1) it had not made its
    determination in writing; and (2) it had used the wrong standard to determine
    whether the proposed project might have a significant effect on the environment.
    Regarding the latter, we construed section 21151 to require preparation of an EIR
    for a nonexempt project ―whenever it can be fairly argued on the basis of
    substantial evidence that the project may have a significant environmental
    impact.‖ (No Oil, supra, at p. 75.) At the trial court‘s direction, Los Angeles had
    applied ―a far more restrictive test that limited use of an EIR to projects which
    may have an ‗important‘ or ‗momentous‘ effect of semi-permanent duration.‖
    (Ibid.) In reaching our conclusion, we cited the following factors: (1) ―the
    preparation of an EIR is the key to environmental protection under CEQA‖ (ibid.);
    (2) the statute speaks, not of projects that will have a significant effect on the
    environment, but of projects that ―may‖ have such effect (id. at p. 83, fn. 16); (3)
    the Legislature intended that CEQA be interpreted to afford the fullest protection
    to the environment within the reasonable scope of the statutory language, but the
    test Los Angeles had applied afforded the least possible protection within the
    statutory language (id. at p. 85); and (4) by ―bar[ring] preparation of an EIR‖ in
    ―close and doubtful cases,‖ the test Los Angeles applied would ―defeat the
    Legislature‘s objective of ensuring that environmental protection serve as the
    29
    guiding criterion in agency decisions‖ (id. at p. 84). Because we concluded that
    Los Angeles had failed to proceed as required by law, in part by applying the
    wrong standard, we expressly declined to decide whether its decision was
    ―supported by substantial evidence.‖ (Id. at p. 75.)
    The Natural Resources Agency has since expressly incorporated No Oil‘s
    fair argument approach into the Guidelines. Guidelines section 15064, subdivision
    (f)(1), now states: ―If the lead agency determines there is substantial evidence in
    the record that the project may have a significant effect on the environment, the
    lead agency shall prepare an EIR (Friends of B Street v. City of Hayward (1980)
    
    106 Cal. App. 3d 988
    ). Said another way, if a lead agency is presented with a fair
    argument that a project may have a significant effect on the environment, the lead
    agency shall prepare an EIR even though it may also be presented with other
    substantial evidence that the project will not have a significant effect (No Oil, Inc.
    v. City of Los Angeles (1974) 
    13 Cal. 3d 68
    ).‖5 If, however, an agency‘s ―initial
    study‖ for a nonexempt project ―shows that there is no substantial evidence that
    the project may have a significant effect‖ on the environment, the agency
    ―prepares a negative declaration‖ (Guidelines, § 15002, subd. (k)(2)) describing
    ―the reasons‖ why no EIR is required (§ 21064).
    The fair argument standard Guidelines section 15064, subdivision (f)(1),
    sets forth applies by its terms to determinations of a lead agency, not of a court.
    Under sections 21168 and 21168.5, judicial review of agency decisions is for
    abuse of discretion. (Laurel Heights II, supra, 6 Cal.4th at p. 1135.) The scope of
    review of an agency‘s application of the fair argument standard is described in
    Friends of “B” Street v. City of Hayward (1980) 
    106 Cal.App.3d 988
    , 1002
    5      This guideline first appeared in 1983 as Guidelines section 15064,
    subdivision (g)(1). (See Guidelines, § 15064, Register 83, No. 29 (July 16, 1983)
    p. 308.)
    30
    (Friends of “B” Street), a decision that section 15064, subdivision (f)(1), cites.
    Friends of “B” Street explained that a reviewing court may not uphold an
    agency‘s decision ―merely because substantial evidence was presented that the
    project would not have [a significant environmental] impact. The [reviewing]
    court‘s function is to determine whether substantial evidence support[s] the
    agency‘s conclusion as to whether the prescribed ‗fair argument‘ could be made.
    If there [is] substantial evidence that the proposed project might have a significant
    environmental impact, evidence to the contrary is not sufficient to support a
    decision to dispense with preparation of an EIR and adopt a negative declaration,
    because it [can] be ‗fairly argued‘ that the project might have a significant
    environmental impact. Stated another way, if the [reviewing] court perceives
    substantial evidence that the project might have such an impact, but the agency
    failed to secure preparation of the required EIR, the agency‘s action is to be set
    aside because the agency abused its discretion by failing to proceed ‗in a manner
    required by law.‘ ‖ (Friends of “B” Street, supra, at p. 1002.)
    There have been several attempts to extend the fair argument standard to
    CEQA determinations other than the one at issue in No Oil, supra, 
    13 Cal.3d 68
    ,
    i.e., whether to prepare an EIR for a nonexempt project. We considered, and
    rejected, one such attempt in Laurel Heights II, which involved an agency‘s
    decision not to recirculate an EIR for public comment. Section 21092.1 requires
    recirculation if ―significant new information is added to‖ an EIR after initial
    circulation and before certification. In Laurel Heights II, a neighborhood
    improvement association argued that in determining whether recirculation is
    required, ―the ‗fair argument‘ test used to review the decision . . . to prepare a
    negative declaration‖ in lieu of an EIR should apply. (Laurel Heights II, supra, 6
    Cal.4th at p. 1134.) We disagreed, explaining: ―[S]ection 21151 commands that
    an EIR must be prepared whenever a project ‗may have a significant effect on the
    31
    environment.‘ (Italics added.) In No Oil . . . , we interpreted section 21151 to
    require preparation of an EIR whenever it can be fairly argued on the basis of
    substantial evidence that the project may have significant environmental impact.
    [Citation.] Our decision, however, expressly acknowledged that judicial review of
    agency decisions under CEQA is governed by sections 21168 (administrative
    mandamus) and 21168.5 (traditional mandamus) and, of course, did not purport to
    alter the standard of review set forth in those statutes. Rather, the ‗fair argument‘
    test was derived from an interpretation of the language of, and policies underlying,
    section 21151 itself. For this reason, the ‗fair argument‘ test has been applied only
    to the decision whether to prepare an original EIR or a negative declaration.
    [Citations.] The Association has advanced no persuasive authority or reasons for
    taking this test out of the context of the statutory language of section 21151 and
    applying it to an agency‘s decision under section 21092.1. [¶] We conclude that
    the substantial evidence standard set forth in section 21168.5 governs the
    [agency‘s] decision not to recirculate the EIR in this case.‖ (Id. at pp. 1134-1135,
    fns. omitted.)
    Several courts, however, have extended the fair argument approach to
    aspects of the determination whether the unusual circumstances exception applies.
    (Voices for Rural Living v. El Dorado Irr. Dist. (2012) 
    209 Cal.App.4th 1096
    ,
    1108 (Voices); Wollmer v. City of Berkeley (2011) 
    193 Cal.App.4th 1329
    , 1350;
    Banker’s Hill, supra, 139 Cal.App.4th at pp. 261-267; Azusa Land Reclamation
    Co. v. Main San Gabriel Basin Watermaster (1997) 
    52 Cal.App.4th 1165
    , 1206;
    Dunn-Edwards Corp. v. Bay Area Air Quality Management Dist. (1992) 
    9 Cal.App.4th 644
    , 654-656.) Other courts have noted judicial disagreement as to
    whether the fair argument standard applies in this context, but have declined to
    decide the issue, finding that the standard‘s application would not have affected
    the result. (Save the Plastic Bag Coalition v. City and County of San Francisco
    32
    (2013) 
    222 Cal.App.4th 863
    , 879; Hines v. California Coastal Commission (2010)
    
    186 Cal.App.4th 830
    , 855; San Lorenzo Valley Community Advocates for
    Responsible Educ. v. San Lorenzo Valley Unified School Dist. (2006) 
    139 Cal.App.4th 1356
    , 1390; Santa Monica Chamber of Commerce v. City of Santa
    Monica (2002) 
    101 Cal.App.4th 786
    , 796 (Santa Monica); Fairbank v. City of Mill
    Valley (1999) 
    75 Cal.App.4th 1243
    , 1259-1260; Ukiah, supra, 2 Cal.App.4th at p.
    728, fn. 7.) The principal supporting authority these courts cite for the fair
    argument standard‘s inapplicability is Centinela Hospital Assn. v. City of
    Inglewood (1990) 
    225 Cal.App.3d 1586
    . There, in rejecting the claim that the
    unusual circumstances exception applied, the court reasoned: ―When appellant
    argues that the facility is located ‗at an extremely sensitive location in terms of
    public usage and traffic,‘ and it ‗will create a health and safety hazard, which in
    turn, will place increased demands on public services such as police and fire
    protection,‘ appellant is asking us to adopt an improper standard of review and
    independently reweigh the evidence. We conclude that substantial evidence
    supports the express findings of the [City of Inglewood Planning] Commission
    and city council as to traffic and public health and safety issues and substantial
    evidence supports the implied finding in the notice of exemption that the facility
    would not cause any significant environmental effects.‖6 (Centinela, at p. 1601.)
    We conclude that both prongs of section 21168.5‘s abuse of discretion
    standard apply on review of an agency‘s decision with respect to the unusual
    circumstances exception. The determination as to whether there are ―unusual
    circumstances‖ (Guidelines, § 15300.2, subd. (c)) is reviewed under section
    21168.5‘s substantial evidence prong. However, an agency‘s finding as to
    6       The courts noting judicial disagreement regarding the applicable standard
    also cite Dehne v. County of Santa Clara (1981) 
    115 Cal.App.3d 827
    , but that
    decision does not mention or discuss the unusual circumstances exception.
    33
    whether unusual circumstances give rise to ―a reasonable possibility that the
    activity will have a significant effect on the environment‖ (Guidelines, § 15300.2,
    subd. (c)) is reviewed to determine whether the agency, in applying the fair
    argument standard, ―proceeded in [the] manner required by law.‖ (§ 21168.5;
    Friends of “B” Street, supra, 106 Cal.App.3d at p. 1002.)
    Whether a particular project presents circumstances that are unusual for
    projects in an exempt class is an essentially factual inquiry, ― ‗founded ―on the
    application of the fact-finding tribunal‘s experience with the mainsprings of
    human conduct.‖ ‘ ‖ (People v. Louis (1986) 
    42 Cal.3d 969
    , 987.) Accordingly,
    as to this question, the agency serves as ―the finder of fact‖ (Save Our Peninsula
    Committee v. Monterey County Board of Supervisors (2001) 
    87 Cal.App.4th 99
    ,
    117), and a reviewing court should apply the traditional substantial evidence
    standard that section 21168.5 incorporates. (Save Our Peninsula Committee, at p.
    117.) Under that relatively deferential standard of review, the reviewing court‘s
    ― ‗role‘ ‖ in considering the evidence differs from the agency‘s. (Western States
    Petroleum Assn. v. Superior Court (1995) 
    9 Cal.4th 559
    , 576.) ― ‗Agencies must
    weigh the evidence and determine ―which way the scales tip,‖ while courts
    conducting [traditional] substantial evidence . . . review generally do not.‘ ‖
    (Ibid.) Instead, reviewing courts, after resolving all evidentiary conflicts in the
    agency‘s favor and indulging in all legitimate and reasonable inferences to uphold
    the agency‘s finding, must affirm that finding if there is any substantial evidence,
    contradicted or uncontradicted, to support it. (Id. at p. 571; see Laurel Heights
    Improvement Assn. v. Regents of University of California (1988) 
    47 Cal.3d 376
    ,
    393 `(Laurel Heights I ) [reviewing court‘s ―task is not to weigh conflicting
    evidence and determine who has the better argument‖ or whether ―an opposite
    conclusion would have been equally or more reasonable‖].)
    34
    As to the whether there is ―a reasonable possibility‖ that an unusual
    circumstance will produce ―a significant effect on the environment‖ (Guidelines,
    § 15300.2, subd. (c)), a different approach is appropriate, both by the agency
    making the determination and by reviewing courts. As we explained in Laurel
    Heights II, supra, 6 Cal.4th at pages 1134-1135, the fair argument standard ―was
    derived from an interpretation of the language of, and policies underlying,‖ the
    statute at issue in No Oil — section 21151 — which ―commands that an EIR must
    be prepared whenever a project ‗may have a significant effect on the
    environment.‘ ‖ (Italics omitted.) As the Court of Appeal observed in Banker’s
    Hill, supra, 139 Cal.App.4th at page 264, there are ―close textual similarities‖
    between this statutory language and the language of Guidelines section 15300.2,
    subdivision (c), which precludes application of categorical exemptions ―where
    there is a reasonable possibility that the activity will have a significant effect on
    the environment due to unusual circumstances.‖ (Italics added.) Notably, we
    observed in No Oil that ―the word ‗may‘ connotes a ‗reasonable possibility . . . .‘ ‖
    (No Oil, supra, 13 Cal.3d at p. 83, fn. 16.) Accordingly, when there are ―unusual
    circumstances,‖ it is appropriate for agencies to apply the fair argument standard
    in determining whether ―there is a reasonable possibility of a significant effect on
    the environment due to unusual circumstances.‖ (Guidelines, § 15300.2, subd.
    (c).) As to this question, the reviewing court‘s function ―is to determine whether
    substantial evidence support[s] the agency‘s conclusion as to whether the
    prescribed ‗fair argument‘ could be made.‖ (Friends of “B” Street, supra, 106
    Cal.App.3d at p. 1002.)
    This bifurcated approach to the questions of unusual circumstances and
    potentially significant effects comports with our construction of the unusual
    circumstances exception to require findings of both unusual circumstances and a
    potentially significant effect. It would be inappropriate for an agency to apply the
    35
    fair argument standard to determine whether unusual circumstances exist. That
    standard is intended to guide the determination of whether a project has a
    potentially significant effect, not whether it presents unusual circumstances.
    While evidence of a significant effect may be offered to prove unusual
    circumstances, circumstances do not become unusual merely because a fair
    argument can be made that they might have a significant effect. Evidence that a
    project may have a significant effect is not alone enough to remove it from a class
    consisting of similar projects that the Secretary has found ―do not have a
    significant effect on the environment.‖ (§ 21084, subd. (a), italics added; cf.
    Laurel Heights II, supra, 6 Cal.4th at p. 1134; No Oil, supra, 13 Cal.3d at p. 83,
    fn. 16 .) Therefore, an agency must weigh the evidence of environmental effects
    along with all the other evidence relevant to the unusual circumstances
    determination, and make a finding of fact. Judicial review of such determinations
    is limited to ascertaining whether they are ―supported by substantial evidence.‖
    (§ 21168.5.)
    On the other hand, when unusual circumstances are established, the
    Secretary‘s findings as to the typical environmental effects of projects in an
    exempt category no longer control. Because there has been no prior review of the
    effects of unusual circumstances, the policy considerations we discussed in No Oil
    apply. An agency must evaluate potential environmental effects under the fair
    argument standard, and judicial review is limited to determining whether the
    agency applied the standard ―in [the] manner required by law.‖ (§ 21168.5.)
    We reject respondents‘ assertion that applying two different standards to
    the unusual circumstances exception is ―fundamentally inconsistent with the legal
    framework for categorical exemptions‖ and would, by making the process ―too
    complicated and cumbersome,‖ ―defeat the Legislature‘s intent in having
    categorical exemptions.‖ As explained above, requiring an agency to apply the
    36
    fair argument standard to determine whether unusual circumstances give rise to ―a
    reasonable possibility that the activity will have a significant effect on the
    environment‖ (Guidelines, § 15300.2, subd. (c)) is fully consistent with CEQA‘s
    framework and the Legislature‘s intent to provide categorical exemptions. Nor,
    for a reviewing court, is there anything particularly ―complicated‖ or
    ―cumbersome‖ about applying section 21168.5‘s substantial evidence prong to
    unusual circumstance determinations, and its ―proceeded in a manner required by
    law‖ prong to determinations as to potentially significant effects. Courts are well
    versed in bringing a variety of considerations to bear in making such
    determinations.
    Contrary to respondents‘ assertion, applying the fair argument standard to
    aspects of the unusual circumstances exception does not conflict with our decision
    in Muzzy Ranch, supra, 
    41 Cal.4th 372
    . The premise of respondents‘ argument is
    that, in Muzzy Ranch, we applied the traditional substantial evidence test in
    reviewing an agency‘s determination under Guidelines section 15061, subdivision
    (b)(3), that a proposed project was not subject to CEQA. However, in Muzzy
    Ranch, we had no occasion to identify the standard of review we applied.
    Moreover, as appellants explain, the language of Guidelines section 15061,
    subdivision (b)(3), is considerably different from the language of the unusual
    circumstances exception; the former applies ―[w]here it can be seen with certainty
    that there is no possibility that the activity in question may have a significant
    effect on the environment‖ (Guidelines, § 15061, subd. (b)(3)), whereas the latter
    applies ―where there is a reasonable possibility that the activity will have a
    significant effect on the environment due to unusual circumstances‖ (Guidelines, §
    15300.2, subd. (c)). Thus, even under respondents‘ reading of Muzzy Ranch,
    applying the fair argument standard in the context of the unusual circumstances
    exception creates no conflict with that decision.
    37
    Finally, and again contrary to respondents‘ assertion, our approach is fully
    consistent with — and is, indeed, affirmatively supported by — the decision in
    Valley Advocates v. City of Fresno (2008) 
    160 Cal.App.4th 1039
    . At issue there
    were the following CEQA provisions: (1) section 21084.1, which provides that
    ―[a] project that may cause a substantial adverse change in the significance of an
    historical resource is a project that may have a significant effect on the
    environment‖; (2) section 21084, subdivision (e), which provides that ―[a] project
    that may cause a substantial adverse change in the significance of a historical
    resource, as specified in Section 21084.1, shall not be exempted from [CEQA]
    pursuant to subdivision (a)‖; and (3) Guidelines section 15300.2, subdivision (f),
    which provides that ―[a] categorical exemption shall not be used for a project
    which may cause a substantial adverse change in the significance of a historical
    resource.‖ The court held that, in applying these provisions, ―the fair argument
    standard does not govern‖ an agency‘s determination of whether a building
    qualifies as a ―historical resource.‖ (Valley Advocates, supra, at p. 1072.)
    However, the court continued, ―once the resource has been determined to be an
    historical resource, then the fair argument standard applies to the question whether
    the proposed project ‗may cause a substantial adverse change in the significance of
    an historical resource‘ [citation] and thereby have a significant effect on the
    environment.‖ (Ibid.) This discussion supports the conclusion that, if ―unusual
    circumstances‖ are established, an agency should apply the fair argument standard
    in determining whether there is ―a reasonable possibility‖ that those circumstances
    will produce ―a significant effect‖ within the meaning of CEQA. (Guidelines, §
    15300.2, subd. (c).)
    C. Lower Court Rulings.
    In reviewing the City‘s determination that the unusual circumstances
    exception does not apply, the trial court identified and made ―two separate
    38
    determinations‖: (1) whether ―there is a reasonable possibility that the activity
    will have a significant effect on the environment‖; and (2) ―whether such
    reasonable possibility of a significant effect is due to unusual circumstances
    associated with the project.‖ It answered the first question in the affirmative,
    explaining in part that, ―[d]espite Respondents‘ criticisms of [Karp‘s] report and
    [his] methodology, and even when discounting the clearly erroneous and
    misleading portions, Dr. Karp‘s opinion‖ regarding the ― ‗probability of seismic
    lurching of oversteepened side-hill fills‘ ‖ ―provides substantial evidence of a fair
    argument of a significant environmental effect consequent to the Project.‖
    However, the court also found that the proposed project did not present ―unusual
    circumstances,‖ explaining: ―Though the Project involves a large house, built in
    the hills on a steep slope, there is nothing so out of the ordinary about such a
    project that it would take it out of the exemption. Moreover, there is no evidence
    to support a finding that any of the circumstances surrounding the Project make it
    ‗unusual.‘ . . . [T]hough it is a large house proposed to be built on a large and steep
    hillside lot with grading and retaining walls, the Project is not so unusual for a
    single family residence, particularly in this vicinity, as to constitute the type of
    unusual circumstances required to support application of this exception.‖
    In reversing the judgment, the Court of Appeal agreed with the trial court
    ―that Karp‘s letters . . . amounted to substantial evidence of a fair argument that
    the proposed construction would result in significant environmental impacts.‖ But
    it disagreed that the unusual circumstances exception applies only if the proposed
    project‘s potentially significant environmental effects are due to unusual
    circumstances. In the Court of Appeal‘s view, ―the fact‖ that the proposed project
    ―may‖ have a significant effect on the environment ―is itself an unusual
    circumstance‖ that ―preclude[s]‖ the City from applying a categorical exemption.
    The Court of Appeal went on to note that it may nevertheless ―be helpful‖ to
    39
    determine ―whether unusual circumstances exist‖ apart from the project‘s
    potentially significant environmental effect. Considering this question de novo, it
    found that, with respect to the Class 3 small structure exemption, the proposed
    project‘s size constitutes such a circumstance. In reaching this result, it reasoned
    that ―whether a circumstance is unusual ‗is judged relative to the typical
    circumstances related to an otherwise typically exempt project,‘ as opposed to the
    typical circumstances in one particular neighborhood.‖ As to the Class 32 in-fill
    development exemption, the court offered no additional analysis.
    It is apparent that neither the trial court nor the Court of Appeal applied
    principles like those we have set out above. Remand for application of the
    standards we announce today is therefore both appropriate and necessary.7
    The Court of Appeal erred in another respect by indicating, as noted above,
    that the unusual circumstances inquiry excludes consideration of ―the typical
    circumstances in one particular neighborhood.‖ In a number of decisions, our
    appellate courts have looked to conditions in the immediate vicinity of a proposed
    project to determine whether the unusual circumstances exception applied.
    (Bloom v. McGurk (1994) 
    26 Cal.App.4th 1307
    , 1315-1316; City of Pasadena v.
    State of California (1993) 
    14 Cal.App.4th 810
    , 826-827; Ukiah, supra, 2
    Cal.App.4th at p. 736.) Indeed, in the only decision the Court of Appeal cited for
    its contrary view — Santa Monica, supra, 
    101 Cal.App.4th 786
     — the court
    7      In reversing based on potential geotechnical effects, the Court of Appeal
    did not address other potential effects appellants allege, including aesthetic and
    view impacts, inconsistencies with land use plans and policies the City has
    adopted for environmental protection, construction-related traffic impacts, and
    permanent traffic impacts related to contemplated fundraising activities at the
    house. Nor did the Court of Appeal address appellants‘ argument that the City‘s
    adoption of a traffic management plan is a mitigation measure that precludes a
    finding that the proposed project is categorically exempt. Rather than address
    these issues here in the first instance, we leave their consideration to the Court of
    Appeal on remand.
    40
    quoted Ukiah on this point and declared it to be ―instructive.‖ (Santa Monica, at
    p. 802.) Insofar as these decisions indicate that local conditions are relevant, we
    agree. In determining whether the environmental effects of a proposed project are
    unusual or typical, local agencies have discretion to consider conditions in the
    vicinity of the proposed project.
    Respondents separately attack the conclusion of both the trial court and the
    Court of Appeal that Karp‘s submissions constitute substantial evidence of a fair
    argument that the proposed project may have a significant environmental effect.
    As earlier noted, Karp opined that the proposed project ―is likely to have very
    significant environmental impacts . . . due to the probability of seismic lurching of
    the oversteepened side-hill fills.‖ Respondents contend that Karp‘s opinion does
    not constitute substantial evidence of a fair argument because it is based on a
    misreading of the plans the City approved. In their view, the evidence in the
    record, including the submissions of Kropp and Toby, conclusively establishes
    that ―the project approved by the City does not involve ‗side-hill fill‘ ‖ and that
    Karp was mistaken in reading the plans otherwise. Because of Karp‘s erroneous
    belief there would be side-hill fill, his opinion, respondents assert, ―is not
    substantial evidence.‖ A finding of potential environmental impacts, respondents
    argue, must be based on the proposed project as actually approved, and may not be
    based on unapproved activities that opponents assert will be necessary because the
    project as approved cannot be built. If the proposed project ―cannot be built as
    approved‖ and applicants want to build a different project, then ―they must return
    to the City for approval of a different project and the City could issue a stop-work
    notice to prevent unauthorized construction.‖
    We agree with respondents that a finding of environmental impacts must be
    based on the proposed project as actually approved and may not be based on
    unapproved activities that opponents assert will be necessary because the project,
    41
    as approved, cannot be built. In Laurel Heights I, supra, 47 Cal.3d at page 395,
    we considered whether there are circumstances under which an EIR must address
    ―future action related to‖ a proposed project. There, the University of California,
    San Francisco (UCSF), had certified an EIR for moving its school of pharmacy to
    100,000 square feet of a 354,000-square-foot building it had purchased. (Id. at p.
    393.) Although UCSF admitted it intended to use the remainder of the building
    when existing tenants left, the EIR it prepared did not consider the potential
    environmental effect of that intended future use. (Id. at pp. 393, 397.) To justify
    this omission, UCSF argued that it had ―not formally decided precisely how [it
    would] use the remainder of the building.‖ (Id. at p. 396.) In rejecting this
    argument, we first held that an EIR for a proposed project must consider the
    potential environmental effects of future expansion if expansion (1) ―is a
    reasonably foreseeable consequence of the initial project‖ and (2) ―will be
    significant in that it will likely change the scope or nature of the initial project or
    its environmental effects.‖ (Ibid.) This standard, we reasoned, properly balances
    the following considerations: (1) delayed review may produce ―bureaucratic and
    financial momentum‖ that ―provid[es] a strong incentive to ignore environmental
    concerns that could be dealt with more easily at an early stage of the project‖ (id.
    at p. 395); (2) ― ‗environmental considerations do not become submerged by
    chopping a large project into many little ones — each with a minimal potential
    impact on the environment — which cumulatively may have disastrous
    consequences‘ [citation]‖; and (3) ―premature environmental analysis may be
    meaningless and financially wasteful‖ (id. at p. 396). We then concluded that
    UCSF‘s EIR had to address the potential effects of future use because there was
    ―telling evidence‖ UCSF had, by the time it prepared the EIR, ―either made
    decisions or formulated reasonably definite proposals as to future uses of the
    building.‖ (Id. at p. 397.) We clarified, however, that an EIR need not discuss
    42
    ―specific future action that is merely contemplated or a gleam in a planner‘s eye.‖
    (Id. at p. 398.)
    We decline to extend Laurel Heights I to situations where project
    opponents claim, not that the proposed project will lead to additional future
    development, but that the proposed project cannot be carried out as approved and
    will require additional work that may or will have a significant environmental
    effect. The latter situation, unlike the former, presents little risk of either
    bureaucratic and financial impediments to proper environmental review or
    piecemeal review of a project with the potential for significant cumulative effects.
    As respondents argue, if a proposed project cannot be built as approved, then the
    project‘s proponents will have to seek approval of any additional activities and, at
    that time, will have to address the potential environmental effects of those
    additional activities. As respondents also argue, if a project opponent‘s opinion
    that unapproved activities may have a significant environmental effect constitutes
    fair argument, then it is doubtful that any project could survive challenge.
    Accordingly, Karp‘s opinion is insufficient as a matter of law insofar as it is based
    on the potential effect of unapproved activities Karp believes will be necessary
    because the project cannot be built as approved.
    This conclusion has implications for respondents‘ claim that, because Karp
    misread the proposed project‘s plans, his opinion is legally insufficient. As part of
    the permit application, applicants submitted a set of architectural plans for the
    project. In opining that the proposed project would result in ―oversteepened side-
    hill fills‖ with potentially significant environmental effects — including ―seismic
    lurching‖ — Karp relied largely, if not entirely, on a page of those plans entitled
    ―TRANSVERSE SECTION LOOKING EAST.‖ In April 2010, during the appeal
    to the city council, Karp stated that this page ―indicates [that] fills [will be] placed
    directly on very steep existing slopes,‖ ―creat[ing] a new slope more than 50º.‖
    43
    However, the plans the Board had already approved three months earlier (along
    with the use permit) did not include this page. Nor, as appellants concede, do the
    project plans the city council ultimately approved include this page.8 Insofar as
    Karp thus based his opinion regarding the project‘s potential effects on side-hill
    fill that has not been approved, his opinion is legally insufficient.9 On remand, the
    Court of Appeal should apply these principles to Karp‘s opinion should it reach
    that point in its analysis.10
    Finally, because reversal and remand is appropriate for reasons explained
    above, we need not resolve respondents‘ claim that the remedy the Court of
    Appeal chose upon finding the proposed project not to be exempt under Class 3 or
    Class 32 — ordering preparation of an EIR — was improper. However, it is
    appropriate to discuss that issue because the question of remedy could arise again
    on remand.
    Section 21168.9 specifically addresses the available remedies for CEQA
    violations. As here relevant, subdivision (a) provides that, upon finding that a
    8       In its resolution affirming the Board‘s decision, the city council stated:
    ―[T]he Council hereby adopts . . . the project plans on Exhibit B.‖ The page on
    which Karp relied does not appear in that exhibit.
    9       Based on other expert evidence before the city council — the letters from
    Kropp and Toby — respondents also assert that Karp misread the omitted page,
    and that what he identified on that page as side-hill fill is actually nothing more
    than the lot‘s current ground surface. In light of our conclusion, we need not
    address this argument.
    10      Respondents also argue that the ―the probability of seismic lurching‖ Karp
    identified is an effect, not of the project, but of Berkeley‘s ―existing earthquake-
    prone environment,‖ and that application of the unusual circumstances exception
    may not be based on evidence of the existing environment‘s impact on a proposed
    project. In California Building Industry Assn. v. Bay Area Air Quality
    Management Dist. (review granted Nov. 26, 2013, S213478), we granted review to
    decide whether CEQA requires an analysis of how existing environmental
    conditions will impact future residents or users of a proposed project. Given this
    fact, and the other errors that require reversal and remand, we do not address this
    claim.
    44
    public agency‘s decision violates CEQA, a court should enter an order that
    includes (1) a mandate that the decision be voided in whole or in part, and/or (2) a
    mandate that the agency ―take specific action as may be necessary to bring
    the . . . decision into compliance with‖ CEQA. (§ 21168.9, subd. (a)(1), (3).)
    Subdivision (b) states that any such order ―shall be made by the issuance of a
    peremptory writ of mandate specifying what action by the public agency is
    necessary to comply with [CEQA].‖ (§ 21168.9, subd. (b), italics added.)
    Consistent with these provisions, we have ordered preparation of an EIR upon
    finding that a public agency had improperly issued a negative declaration for a
    proposed project (Communities for a Better Environment v. South Coast Air
    Quality Management Dist. (2010) 
    48 Cal.4th 310
    , 320), and upon finding that a
    certified EIR was inadequate (Laurel Heights I, supra, 47 Cal.3d at p. 388).
    However, as respondents note, subdivision (c) of section 21168.9 provides
    in part that ―[n]othing in this section authorizes a court to direct any public agency
    to exercise its discretion in any particular way.‖ In Voices, supra, 209
    Cal.App.4th at page 1113, the Court of Appeal held that, upon finding that an
    agency erred in applying a categorical exemption, the trial court had ―exceeded its
    authority‖ in ordering the agency to prepare an EIR. ―How an agency complies
    with CEQA,‖ the Court of Appeal reasoned, ―is a matter first left to the agency‘s
    discretion. Having determined the project was not exempt from CEQA, the court
    should have ordered [the agency] to proceed with further CEQA compliance,
    which in this case would have been the preparation of an initial study and a
    determination of whether further environmental review would require an EIR or a
    mitigated negative declaration.‖ (Ibid.) Consistent with these authorities, if, on
    remand, the Court of Appeal determines that neither of the categorical exemptions
    discussed above applies, then it may order preparation of an EIR only if, under the
    45
    circumstances, the City would lack discretion to apply another exemption or to
    issue a negative declaration, mitigated or otherwise.
    III. DISPOSITION
    The Court of Appeal‘s judgment is reversed and the matter is remanded for
    further proceedings consistent with this opinion.
    CHIN, J.
    WE CONCUR:
    CANTIL-SAKAUYE, C. J.
    CORRIGAN, J.
    BAXTER, J.*
    BOREN, J.**
    _____________________________
    *      Retired Associate Justice of the Supreme Court, assigned by the Chief
    Justice pursuant to article VI, section 6 of the California Constitution.
    **     Administrative Presiding Justice of the Court of Appeal, Second Appellate
    District, Division Two, assigned by the Chief Justice pursuant to article VI,
    section 6 of the California Constitution.
    46
    CONCURRING OPINION BY LIU, J.
    I agree with today‘s opinion that ―a finding of environmental impacts must
    be based on the proposed project as actually approved and may not be based on
    unapproved activities that opponents assert will be necessary because the project,
    as approved, cannot be built.‖ (Maj. opn., ante, at p. 42.) This rule will not lead
    to evasion of the environmental review requirements of the California
    Environmental Quality Act (CEQA) because presumably a developer‘s failure to
    build the project as approved will be remedied by the local agency that approved
    the project. Where opponents of a project make a credible argument that it cannot
    be built as approved, a trial court may exercise its discretion to retain continuing
    jurisdiction after rendering a judgment in order to ensure CEQA compliance. (See
    2 Witkin, Cal. Procedure, Jurisdiction, § 420, pp. 1070–1071; City of Pasadena v.
    City of Alhambra (1949) 
    33 Cal.2d 908
    , 936 [court reserves jurisdiction to modify
    water rights judgment ― ‗in the event material change be found or any such
    abandonment or forfeiture be established‘ ‖].) In this case, because the trial court
    and Court of Appeal did not limit environmental review to projects actually
    approved, I agree that reversal and remand are warranted. (Maj. opn., ante, at
    pp. 41–44.)
    I do not agree, however, with the court‘s reading of section 15300.2,
    subdivision (c) of the CEQA guidelines (Cal. Code Regs., tit. 14, § 15000 et seq.
    1
    (Guidelines)) or with the court‘s novel and unnecessarily complicated approach to
    the standard of review. Section 15300.2, subdivision (c) (hereafter
    section 15300.2(c)) provides that a categorical exemption from CEQA review
    shall not apply when ―there is a reasonable possibility that the activity will have a
    significant effect on the environment due to unusual circumstances.‖ The court
    says this language establishes two distinct requirements for section 15300.2(c)‘s
    applicability: (1) there must be a reasonable possibility the project will have
    significant environmental effects and (2) those effects must be due to unusual
    circumstances. But, as explained below, a project falling within a categorical
    exemption is, by definition, a project belonging to a class of projects that does not
    have significant environmental effects. (See Pub. Resources Code, § 21084,
    subd. (a).) When there is a reasonable possibility that a project otherwise covered
    by a categorical exemption will have a significant environmental effect, it
    necessarily follows that the project presents unusual circumstances. In other
    words, the reasonable possibility of a significant environmental effect means that
    some circumstance of the project is not usual in comparison to the typical project
    in the exempt category. Instead of comprising a distinct requirement, the phrase
    ―unusual circumstances‖ in section 15300.2(c) simply describes the nature of a
    project that, while belonging to a class of projects that typically have no
    significant environmental effects, nonetheless may have such effects. The sole
    question for courts reviewing agency determinations under section 15300.2(c) is
    whether substantial evidence supports a fair argument that the project will have
    significant environmental effects.
    It is unfortunate that today‘s opinion, instead of simplifying the law in
    accordance with the CEQA statute and guidelines, adds further complexity to an
    area that many courts, practitioners, and citizens already find difficult to navigate.
    Nevertheless, I expect that after today‘s decision, as before, courts reviewing
    2
    agency determinations under section 15300.2(c) will be guided by that guideline‘s
    basic purpose, which echoes the statutory mandate: to ensure that projects with a
    reasonable possibility of significant environmental effects are not exempted from
    CEQA review.
    I.
    The main purpose of environmental review under CEQA is to ―identify the
    significant effects on the environment of a project‖ and to identify project
    alternatives and feasible mitigation measures. (Pub. Resources Code, § 21002.1,
    subd. (a); all statutory references are to this code unless otherwise indicated.)
    Consistent with that purpose, the Legislature created categorical exemptions and
    directed the Secretary of the Natural Resources Agency (the Secretary) to list
    classes of projects exempt from CEQA review. Section 21084, subdivision (a)
    (hereafter section 21084(a)) provides: ―The guidelines prepared and adopted
    pursuant to Section 21083 shall include a list of classes of projects that have been
    determined not to have a significant effect on the environment and that shall be
    exempt from this division. In adopting the guidelines, the Secretary of the Natural
    Resources Agency shall make a finding that the listed classes of projects referred
    to in this section do not have a significant effect on the environment.‖ (Italics
    added.) Thus, section 21084(a) instructs the Secretary to exempt from CEQA
    review only classes of projects that do not have a significant effect on the
    environment.
    The exempt classes of projects listed by the Secretary stand in contrast to
    statutory exemptions created by the Legislature. The latter include certain kinds
    of affordable housing (§ 21159.23), certain high priority transit projects
    (§ 21155.1), and the construction of certain prisons (§§ 21080.01, 21080.02). The
    statutory exemptions are not based on any determination that the exempt projects
    will not have significant environmental effects. Instead, they are based on the
    3
    Legislature‘s determination that each of the exemptions ―promote[s] an interest
    important enough to justify forgoing the benefits of environmental review.‖
    (Napa Valley Wine Train, Inc. v. Public Utilities Com. (1990) 
    50 Cal.3d 370
    , 382.)
    The categorical exemptions authorized by section 21084(a) are fundamentally
    different. They are not based on a judgment that certain categories of projects
    should be exempt despite their potential effect on the environment. They are
    based on a wholesale judgment that projects within the exempt category will not
    have significant environmental effects.
    The fact that a categorical exemption reflects a wholesale judgment about a
    class of projects, and not an individual judgment about a particular project, gives
    rise to the interpretive question before us. A class of projects ―determined not to
    have a significant effect on the environment‖ (§ 21084(a)) — for example, a
    single-family residence — may turn out to be overinclusive insofar as it includes
    some projects that fit the category but nevertheless may have significant
    environmental effects. How are such outliers to be treated under the CEQA
    scheme?
    One approach would be to say that section 21084(a) permits such
    overinclusion because most projects in an exempt class will not have significant
    environmental effects and the efficiency gains of exempting the entire class
    outweigh the value of requiring CEQA review of the few projects in the class that
    may have significant effects. But neither the court nor any party has advanced this
    theory, and for good reason.
    In Wildlife Alive v. Chickering (1976) 
    18 Cal.3d 190
    , 205–206
    (Chickering), we said that ―no regulation is valid if its issuance exceeds the scope
    of the enabling statute. [Citations.] The [S]ecretary is empowered to exempt only
    those activities which do not have a significant effect on the environment. (Pub.
    Resources Code, § 21084.) It follows that where there is any reasonable
    4
    possibility that a project or activity may have a significant effect on the
    environment, an exemption would be improper.‖ Section 15300.2(c), promulgated
    shortly after Chickering, was an attempt to codify Chickering and its
    understanding of section 21084(a). A portion of section 15300.2‘s rulemaking file
    reproduced by appellants confirms this regulatory intent, and respondents do not
    suggest otherwise. (See 1 Kostka & Zischke, Practice Under the California
    Environmental Quality Act (2d ed. 2008) § 5.72, p. 5-62 (1 Kostka & Zischke)
    [§ 15300.2(c) ―adopted to codify the court‘s ruling‖ in Chickering that the
    Secretary ―may exempt only activities that do not have a significant effect on the
    environment‖]; Communities for a Better Environment v. California Resources
    Agency (2002) 
    103 Cal.App.4th 98
    , 129 (Communities for a Better Environment)
    [§ 15300.2(c) exception to categorical exemptions was ―based on the Chickering
    decision‖].)
    Section 15300.2(c) reads in full: ―Significant Effect. A categorical
    exemption shall not be used for an activity where there is a reasonable possibility
    that the activity will have a significant effect on the environment due to unusual
    circumstances.‖ This language is one of six provisions under the heading
    ―Exceptions‖ in section 15300.2 of the CEQA guidelines. Like section
    15300.2(c), each of the other five provisions makes the categorical exemptions
    authorized by section 21084(a) inapplicable to projects that, while belonging to an
    exempt class, have certain characteristics that raise environmental concerns. (See
    §§ 15300.2, subd. (a) [exception for ―a project . . . ordinarily insignificant in its
    impact on the environment [that] may in a particularly sensitive environment be
    significant‖], 15300.2, subd. (b) [exception for ―successive projects of the same
    type in the same place‖ whose ―cumulative impact . . . over time is significant‖],
    15300.2, subd. (d) [exception for ―a project which may result in damage to scenic
    resources . . . within . . . a state scenic highway‖], 15300.2, subd. (e) [exception for
    5
    a project located on a hazardous waste site], 15300.2, subd. (f) [exception for a
    project that may adversely affect a historical resource].)
    This regulatory structure — categorical exemptions, with various
    exceptions to the exemptions — confirms that ―a categorical exemption authorized
    by CEQA section 21084 is an exemption from CEQA for a class of projects that
    the Resources Agency determines will generally not have a significant effect on
    the environment.‖ (Communities for a Better Environment, supra, 103
    Cal.App.4th at p. 127; see Azusa Land Reclamation Co. v. Main San Gabriel
    Basin Watermaster (1997) 
    52 Cal.App.4th 1165
    , 1206 (Azusa) [a categorical
    exemption identifies ―a class of activities that does not normally threaten the
    environment‖ (italics added)].) The CEQA guidelines anticipate the
    overinclusivity of categorical exemptions and address the problem by establishing
    a list of exceptions.
    In construing section 15300.2(c), it is worth noting that the title of the
    provision is ―Significant Effect.‖ Hence I shall refer to section 15300.2(c) as the
    ―significant effect exception.‖ In calling section 15300.2(c) the ―unusual
    circumstances exception,‖ today‘s opinion ignores the title and places primary
    emphasis on a term that the provision itself does not emphasize.
    As the court acknowledges, the term ―unusual circumstances‖ first
    appeared in the context of CEQA review in Friends of Mammoth v. Board of
    Supervisors (1972) 
    8 Cal.3d 247
     (Friends of Mammoth), and this usage is key to
    understanding section 15300.2(c). In Friends of Mammoth, we said that ―common
    sense tells us that the majority of private projects for which a government permit
    or similar entitlement is necessary are minor in scope — e.g., relating only to the
    construction, improvement, or operation of an individual dwelling or small
    business — and hence, in the absence of unusual circumstances, have little or no
    effect on the public environment. Such projects, accordingly, may be approved
    6
    exactly as before the enactment of the [CEQA].‖ (Id. at p. 272, italics added.) We
    did not suggest that a finding of ―unusual circumstances‖ was a prerequisite to
    CEQA review. Rather, we used that phrase in the course of acknowledging that
    private projects generally do not have significant effects on the environment, and
    so when they do, such effects will be due to unusual circumstances. Reading
    ―unusual circumstances‖ in this straightforward manner squares section
    15300.2(c) with both Friends of Mammoth and Chickering.
    This understanding of ―unusual circumstances‖ is restated in Communities
    for a Better Environment, supra, 
    103 Cal.App.4th 98
    , a case concerning the in-fill
    development exemption under section 15332 of the CEQA guidelines. In
    explaining that environmental effects not mentioned in section 15332, such as
    aesthetics or health and safety impacts, must be considered in determining the
    exemption‘s applicability, the court said: ―These other environmental effects . . .
    would constitute ‗unusual circumstances‘ under this exception for a project that
    otherwise meets the Guidelines section 15332 criteria. This is because a project
    that does meet the comprehensive environmentally protective criteria of section
    15332 normally would not have other significant environmental effects; if there
    was a reasonable possibility that the project would have such effects, those effects
    would be ‗unusual circumstances‘ covered by the section 15300.2, subdivision (c)
    exception.‖ (Communities for a Better Environment, at p. 129.)
    In sum, when there is a reasonable possibility of a significant
    environmental effect from a project belonging to a class that generally does not
    have such effects, the project necessarily presents ―unusual circumstances,‖ and
    section 15300.2(c) applies.
    7
    II.
    Today‘s opinion objects that this reading of section 15300.2(c) would result
    in categorically exempt projects being treated the same as nonexempt projects,
    thereby undermining the purpose of categorical exemptions. ―Try as they might,‖
    the court says, ―appellants can identify no purpose or effect of the categorical
    exemption statutes if, as they assert, a showing of potential environmental effect
    precludes application of all categorical exemptions.‖ (Maj. opn., ante, at p. 16.)
    ―[T]o establish the unusual circumstances exception, it is not enough for a
    challenger merely to provide substantial evidence that the project may have a
    significant effect on the environment, because that is the inquiry CEQA requires
    absent an exemption. (§ 21151.) Such a showing is inadequate to overcome the
    Secretary‘s determination that the typical effects of a project within an exempt
    class are not significant for CEQA purposes.‖ (Id. at pp. 20–21.) The court is thus
    led to conclude that the term ―due to unusual circumstances‖ sets forth a
    requirement separate and distinct from ―a reasonable possibility of significant
    effects‖ in section 15300.2(c). In turn, the court devises a novel ―bifurcated‖
    standard of review that evaluates whether there is a reasonable possibility of a
    significant environmental effect under the fair argument standard, while evaluating
    whether significant effects are due to unusual circumstances under a deferential
    substantial evidence standard. (Maj. opn., ante, at pp. 34–37.) This approach, the
    court suggests, is necessary in order to treat categorically exempt projects
    differently from nonexempt projects and thereby realize the purpose of categorical
    exemptions.
    But the major premise of the court‘s reasoning is faulty, for there are two
    reasons why it is not true that categorical exemptions would have no value if we
    interpret section 15300.2(c) to apply whenever there is a reasonable possibility of
    significant environmental effects.
    8
    First, when an agency has determined that a project falls within an exempt
    category, the project enjoys a considerable procedural advantage. For any project
    not covered by a categorical or other exemption, the reviewing agency has the
    burden of conducting an initial study into whether the project will have significant
    environmental effects. (See Guidelines, § 15063, subd. (a).) The project may
    proceed without further environmental review only if the agency issues a negative
    declaration identifying the project‘s environmental effects and explaining why
    they are not significant. (See id., § 15063, subd. (b)(2); 1 Kostka & Zischke,
    supra, § 6.2, pp. 6-6 to 6-7.) Notice and public review and comment are required
    of a negative declaration, and an agency must consider comments and potentially
    modify its conclusions in response to those comments. (See 1 Kostka & Zischke,
    supra, §§ 7.10, pp. 7-9 to 7-10; 7.19, pp. 7-16 to 7-17.)
    By contrast, an agency finding that a project falls into an exempt category
    need not follow any particular procedure nor include any written determination,
    and the agency need not undertake an initial study or adopt a negative declaration.
    (See 1 Kostka & Zischke, supra, § 5.114, pp. 5-100 to 5-101.) When an agency
    finds that a project is subject to a categorical exemption, it impliedly finds that it
    has no significant environmental effect, and the burden shifts to the challengers of
    the proposed project to produce evidence that the project will have a significant
    effect. (Id. at § 5.71, pp. 5-61 to 5-62 and cases cited therein.) Once an agency
    finds a project categorically exempt, it is the project opponent‘s burden to produce
    evidence that the significant effect exception applies.
    This procedural advantage should not be underestimated. In many cases,
    categorical exemptions are not litigated, and the applicability of the exemption is
    evident. In the mine run of cases, the efficiency gains of sparing the agency the
    task of conducting an initial study and issuing a negative declaration provide a
    strong policy justification for categorical exemptions. Moreover, as is generally
    9
    true of burden allocations in the law, in cases where an exemption‘s applicability
    presents a close issue, requiring the challenger to show the reasonable possibility
    of a significant effect, instead of requiring the agency to show no such effects, can
    be determinative.
    The court says this procedural advantage is ―largely illusory‖ because ―an
    agency may not apply a categorical exemption without considering evidence in its
    files of potentially significant effects, regardless of whether that evidence comes
    from its own investigation, the proponent‘s submissions, a project opponent, or
    some other source.‖ (Maj. opn., ante, at p. 18.) But an agency‘s obligation to
    consider evidence in its files of potentially significant effects can hardly be
    equated with an agency‘s obligation, in the case of a nonexempt project, to
    undertake an initial study of the project‘s environmental effects, to solicit and
    consider public comments on the study, and to issue a negative declaration
    explaining why potential environmental impacts would not be significant. The
    procedural burdens falling on agencies when they review nonexempt projects are
    considerably greater than when they review categorically exempt projects. The
    court‘s suggestion to the contrary will certainly come as news to the agencies that
    undertake these different review procedures.
    Moreover, an agency finding that a project falls into an exempt category
    confers a second advantage. As the court observes, the Secretary had to interpret
    the meaning of ―significant effects‖ in order to identify classes of projects with no
    significant effects pursuant to section 21084(a). The Secretary‘s designation of an
    exempt category reflects a judgment that projects in the category typically do not
    have significant environmental effects, and this judgment is entitled to
    considerable weight. When an opponent seeks to subject such a project to CEQA
    review, the proponent can make two comparative arguments (assuming they are
    supported by evidence) that are unavailable in the case of a nonexempt project.
    10
    First, the proponent can argue that the project‘s effects are typical of the effects
    generated by projects in the exempt category, such that few or no projects in the
    category would be exempt if the effects were deemed significant. Second, the
    proponent can argue that the project‘s dimensions or features are not unusual
    compared to typical projects in the exempt category, thereby suggesting that the
    project is similar to those that the Secretary has determined not to have a
    significant environmental effect. The availability of these arguments shows that
    the phrase ―due to unusual circumstances‖ is not ―meaningless surplusage.‖ (Maj.
    opn., ante, at p. 20.) Such arguments make it more likely that a project belonging
    to an exempt category will be able to bypass the environmental review that would
    otherwise be required in the absence of any categorical exemption. (See, e.g., San
    Francisco Beautiful v. City and County of San Francisco (2014) 
    226 Cal.App.4th 1012
    , 1025 (San Francisco Beautiful); Fairbank v. City of Mill Valley (1999) 
    75 Cal.App.4th 1243
    , 1260 (Fairbank); Association for Protection of Environmental
    Values in Ukiah v. City of Ukiah (1991) 
    2 Cal.App.4th 720
    , 736 (Ukiah).
    The court says this advantage is also ―illusory‖ because ―evidence a project
    proponent offers to show that the project will only have typical effects,
    dimensions, and features is irrelevant if a project opponent can make a mere fair
    argument that those effects, dimensions, or features are not typical, or that the
    project will have a significant environmental effect.‖ (Maj. opn., ante, at p. 19.)
    But evidence of typicality is surely relevant to whether a project opponent can
    make a fair argument of atypical features or significant effects. This is confirmed
    by the cases just cited (San Francisco Beautiful, Fairbank, and Ukiah), each of
    which relies on such comparative arguments in finding no substantial evidence of
    a fair argument of significant effects. The court nowhere suggests these cases
    erred in their reasoning or results. The fact that comparative arguments may not
    11
    always defeat a fair argument of significant effects does not negate their value in
    the cases where they do.
    Today‘s opinion also contends that my reading of section 15300.2(c) puts a
    project proponent who claims a categorical exemption in the same position as the
    proponent of a nonexempt project who claims the common sense exemption in
    Guidelines section 15061, subdivision (b)(3). (Maj. opn., ante, at p. 17.) But the
    common sense exemption is available only when the agency, based on the record
    evidence, meets its burden of demonstrating ―with certainty that there is no
    possibility that the activity in question may have a significant effect on the
    environment.‖ (Guidelines, § 15061, subd. (b)(3), italics added; see Muzzy Ranch
    Co. v. Solano County Airport Land Use Com. (2007) 
    41 Cal.4th 372
    , 386–387.)
    This exacting requirement exceeds an agency‘s obligation, before applying a
    categorical exemption, to consider the evidence in its files and preliminarily rule
    out a reasonable possibility of significant effects. Indeed, if an agency could
    apply the common sense exemption to a project not covered by a categorical
    exemption simply by making a preliminary determination based on evidence in its
    files that there is no reasonable possibility of significant effects, then the common
    sense exemption would swallow the general rule that an agency must conduct an
    initial study to determine whether a project not covered by a categorical exemption
    will have significant effects. (See Guidelines, § 15063, subd. (a).)
    An agency may find that a project falls within a categorical exemption
    without first making an express or definitive finding that no section 15300.2
    exception applies; the burden is on the party challenging the categorical exemption
    to show that an exception applies. (Committee to Save Hollywoodland Specific
    Plan v. City of Los Angeles (2008) 
    161 Cal.App.4th 1168
    , 1186–1187.) In
    addition, project proponents seeking to invoke a categorical exemption may
    employ comparative arguments that are not available to project proponents
    12
    seeking to invoke the common sense exemption. Thus, the availability of the
    common sense exemption for projects meeting its narrow standard of ―certainty‖
    does not negate the advantages that a categorical exemption confers.
    The court is thus mistaken that the categorical exemption statutes have ―no
    purpose or effect . . . if . . . a showing of potential environmental effect precludes
    application of all categorical exemptions.‖ (Maj. opn., ante, at p. 16.) Without
    this erroneous premise, there is no reason to construe ―due to unusual
    circumstances‖ as an independent requirement in section 15300.2(c) or to adopt a
    separate standard of review for the determination of ―unusual circumstances.‖ As
    explained above, this approach is at odds with section 15300.2(c)‘s origins in
    Chickering and Friends of Mammoth. Section 15300.2(c) affirms the principle
    that ―where there is any reasonable possibility that a project or activity may have a
    significant effect on the environment, an exemption would be improper.‖
    (Chickering, supra, 18 Cal.3d at p. 206.) And just as a project belonging to an
    exempt class will have no significant effects ―in the absence of unusual
    circumstances‖ (Friends of Mammoth, supra, 8 Cal.3d at p. 272), a project that
    may have significant effects, despite belonging to an exempt class, is necessarily a
    project that presents unusual circumstances. The only question for a court
    reviewing an agency‘s section 15300.2(c) determination is whether substantial
    evidence supports a fair argument that the project will have significant
    environmental effects. (See Friends of “B” Street v. City of Hayward (1980) 
    106 Cal.App.3d 988
    , 1002.) It need not be more complicated than that.
    Today‘s decision ventures a panoply of reasons why Chickering should not be
    read to mean what it says, including the opaque contention that Chickering‘s
    interpretation of section 21084(a) somehow violates ―the Legislature‘s express
    directive in section 21083.1 ‗not [to] interpret‘ the CEQA statutes and the Guidelines
    ‗in a manner which imposes procedural or substantive requirements beyond those‘ the
    13
    statutes and the Guidelines ‗explicitly state[].‘ ‖ (Maj. opn., ante, at p. 24.) But the
    court‘s reluctance to follow Chickering is ultimately based not on the language or
    legislative history of section 21084(a), but on the premise that reading section
    21084(a) and section 15300.2(c) in harmony with Chickering would deprive
    categorical exemptions of any purpose or effect. Because this premise is flawed, so is
    the court‘s haphazard effort to minimize Chickering‘s simple and sensible reading of
    section 21084(a).
    III.
    It is true that over the years, the Courts of Appeal have divided on whether
    ―unusual circumstances‖ and ―significant effects‖ are distinct requirements in
    section 15300.2(c). However, when one examines the reasoning of the many
    cases applying section 15300.2(c), it is clear that ―unusual circumstances‖ and
    ―significant effects‖ have invariably traveled together. In the nearly four decades
    since section 15300.2(c) was adopted, no published case has ever found or even
    hinted that a project that belongs to an exempt category yet has a reasonable
    possibility of significant environmental effects may nonetheless evade CEQA
    review on the ground that the effects are not due to unusual circumstances. The
    only court on record to have reached such a conclusion is the trial court in this
    case. But, as today‘s opinion suggests, that conclusion is unlikely to stand. The
    absence of case law finding a reasonable possibility of significant effects but no
    unusual circumstances further confirms that section 15300.2(c) boils down to one
    inquiry, not two.
    Indeed, most courts applying section 15300.2(c) have focused directly on
    whether there is a reasonable possibility that the project will have significant
    environmental effects. (See, e.g., North Coast Rivers Alliance v. Westlands Water
    Dist. (2014) 
    227 Cal.App.4th 832
    , 871–874 [finding no evidence of possible
    14
    significant environmental effects while assuming without deciding that there were
    ―unusual circumstances‖]; Banker’s Hill, Hillcrest, Park West Community
    Preservation Group v. City of San Diego (2006) 
    139 Cal.App.4th 249
    , 278–281
    [rejecting application of the exception on the ground that there were no significant
    environmental effects]; San Lorenzo Valley Community Advocates for Responsible
    Education v. San Lorenzo Valley Unified School Dist. (2006) 
    139 Cal.App.4th 1356
    , 1392–1394 (San Lorenzo) [no substantial evidence of significant
    environmental effects]; Santa Monica Chamber of Commerce v. City of Santa
    Monica (2002) 
    101 Cal.App.4th 786
    , 800–801 (Santa Monica) [only effects of
    adopting a new preferred parking zone were socioeconomic, not environmental,
    and therefore not cognizable under CEQA]; Apartment Assn. of Greater Los
    Angeles v. City of Los Angeles (2001) 
    90 Cal.App.4th 1162
    , 1175–1176
    [insufficient evidence of significant effects]; City of Pasadena v. State of
    California (1993) 
    14 Cal.App.4th 810
    , 827–834 [rejecting various arguments that
    a parole office located in downtown Pasadena would have significant
    environmental effects]; Centinela Hospital Assn. v. City of Inglewood (1990) 
    225 Cal.App.3d 1586
    , 1601 (Centinela) [substantial evidence supported finding of no
    significant environmental effect]; McQueen v. Board of Directors (1988) 
    202 Cal.App.3d 1136
    , 1149 [known existence of hazardous materials on the property
    threatening the environment brings the project within the exception].)
    Among cases that have focused on ―unusual circumstances,‖ it is evident
    that courts have treated unusual circumstances as a proxy for significant effects.
    In Wollmer v. City of Berkeley (2011) 
    193 Cal.App.4th 1329
    , 1350–1352, for
    example, the court titled one part of its opinion ―No Unusual Circumstances
    Preventing Categorical Exemption‖ and then proceeded to find no substantial
    evidence of potential significant environmental effects. In Voices for Rural Living
    v. El Dorado Irrigation Dist. (2012) 
    209 Cal.App.4th 1096
    , 1108–1113, the court
    15
    concluded that a casino requiring a high volume of water usage was an unusual
    circumstance for a project within the ―small facilities‖ exemption, and it then
    proceeded to find that such high-volume water usage presented the potential for
    significant environmental risks. Other courts have employed similar reasoning.
    (See Bloom v. McGurk (1994) 
    26 Cal.App.4th 1307
    , 1315–1316 [―existing
    facilities‖ exemption applied to medical waste facility, and there were no ―unusual
    circumstances‖ because the facility was located in an area zoned for heavy
    industry and not adjacent to a residential area that might be adversely affected by
    such a facility]; Azusa, supra, 52 Cal.App.4th at p. 1207 [finding landfill
    ―unusual‖ because it overlay a major drinking water aquifer and presented a
    substantial risk of pollution].) Again, it appears that no court, other than the trial
    court here, has ever found a reasonable possibility of significant effects while also
    finding that the effects were not due to unusual circumstances.
    As for the proper standard of review, many courts have held that the fair
    argument test applies. (Maj. opn., ante, at pp. 32–33 [citing cases].) One older
    case has disagreed, holding that section 15300.2(c) does not apply if there is
    substantial evidence supporting the agency‘s conclusion that the project will not
    generate significant effects. (Centinela, supra, 225 Cal.App.3d at p. 1601.) As
    today‘s opinion notes, ―[o]ther courts have noted judicial disagreement as to
    whether the fair argument standard applies in this context, but have declined to
    decide the issue, finding that the standard‘s application would not have affected
    the result.‖ (Maj. opn., ante, at p. 33, citing Save the Plastic Bag Coalition v. City
    and County of San Francisco (2013) 
    222 Cal.App.4th 863
    , 879; Hines v.
    California Coastal Commission (2010) 
    186 Cal.App.4th 830
    , 855; San Lorenzo,
    supra, 139 Cal.App.4th at p. 1390; Santa Monica, supra, 101 Cal.App.4th at
    p. 796; Fairbank, supra, 75 Cal.App.4th at pp. 1259–1260; Ukiah, supra, 2
    Cal.App.4th at p. 728, fn. 7.) In each of these cases, the court found no substantial
    16
    evidence supporting a fair argument that the project would have significant
    environmental effects.
    Thus, courts have overwhelmingly used the fair argument standard in
    reviewing the applicability of the significant effect exception either because they
    believed it was the appropriate standard or because they assumed it was. For more
    than two decades, courts have not felt the need to resolve the question of the
    proper standard because the fair argument standard has proven adequate to the task
    of ferreting out bogus CEQA challenges that would subject categorically exempt
    projects to unnecessary environmental review. The ultimate touchstone of all of
    these courts‘ inquiries has been whether there is a reasonable possibility that the
    project would have significant environmental effects.
    Today‘s opinion observes that ―evidence that the project will have a
    significant effect does tend to prove that some circumstance of the project is
    unusual.‖ (Maj. opn., ante, at p. 21.) This observation, though understating the
    real relationship between ―significant effects‖ and ―unusual circumstances,‖
    authorizes courts applying section 15300.2(c) to continue reasoning the way they
    have been doing for years — i.e., focusing their inquiry on whether there is a
    reasonable possibility that the project will have significant environmental effects.
    Indeed, before a project has been subject to environmental review, the only thing
    that courts are generally positioned to assess with confidence is whether there is a
    reasonable possibility of significant environmental effects. (See No Oil, Inc. v.
    City of Los Angeles (1974) 
    13 Cal.3d 68
    , 84–85.) Even under the cumbersome
    rules set forth today, it is hard to imagine that any court, upon finding a reasonable
    possibility of significant effects under the fair argument standard, will ever be
    compelled to find no unusual circumstances and thereby uphold the applicability
    of a categorical exemption. Rather, courts may continue to affirm in practice what
    we have stated as a simple principle: ―where there is any reasonable
    17
    possibility that a project or activity may have a significant effect on the
    environment, an exemption would be improper.‖ (Chickering, supra, 18 Cal.3d at
    p. 206.)
    Although I join the court in reversing and remanding for further
    proceedings, I would hold that the Court of Appeal did not err in its reading of
    section 15300.2(c).
    LIU, J.
    I CONCUR:
    WERDEGAR, J.
    18
    See last page for addresses and telephone numbers for counsel who argued in Supreme Court.
    Name of Opinion Berkeley Hillside Preservation v. City of Berkeley
    __________________________________________________________________________________
    Unpublished Opinion
    Original Appeal
    Original Proceeding
    Review Granted XXX 
    203 Cal.App.4th 656
    Rehearing Granted
    __________________________________________________________________________________
    Opinion No. S201116
    Date Filed: March 2, 2015
    __________________________________________________________________________________
    Court: Superior
    County: Alameda
    Judge: Frank Roesch
    __________________________________________________________________________________
    Counsel:
    Brandt-Hawley Law Group and Susan Brandt-Hawley for Plaintiffs and Appellants.
    Michael W. Graf for Center for Biological Diversity and High Sierra Rural Alliance as Amici Curiae on
    behalf of Plaintiffs and Appellants.
    Chatten-Brown & Carstens, Jan Chatten-Brown, Douglas P. Carstens; Law Offices of Michael W. Stamp,
    Michael W. Stamp and Molly Erickson for Planning and Conservation League, Endangered Habitats
    League, Inc., California Preservation Foundation, Save Our Heritage Organisation, Save Our Carmel River
    and The Open Monterey Project as Amici Curiae on behalf of Plaintiffs and Appellants.
    Veneruso & Moncharsh and Leila H. Moncharsh for Berkley Architectural Heritage Association as Amicus
    Curiae on behalf of Plaintiffs and Appellants.
    Zach Cowan, City Attorney, and Laura McKinney, Deputy City Attorney, for Defendants and Respondents.
    Perkins Coie, Stephen L. Kostka and Barbara J. Schussman for Building Industry Association of the Bay
    Area as Amicus Curiae on behalf of Defendants and Respondents.
    Downey Brand, Christian L. Marsh, Andrea P. Clark and Graham St. Michel for Association of California
    Water Agencies as Amicus Curiae on behalf of Defendants and Respondents.
    Meyers, Nave, Riback, Silver & Wilson, Amrit S. Kulkarni and Julia L. Bond for Real Parties in Interest
    and Respondents.
    Cox, Castle & Nicholson, Michael H. Zischke and Andrew B. Sabey for California Building Industry
    Association, California Business Properties Association and Building Industry Legal Defense Foundation
    as Amici Curiae on behalf of Defendants and Respondents and Real Parties in Interest and Respondents.
    1
    Page 2 – S20116 – counsel continued
    Counsel:
    Lozano Smith, Harold M. Freiman, Kelly M. Rem; Charles F, Robinson and Kelly L. Drumm for
    California School Boards Association‘s Education Legal Alliance, The Regents of the University of
    California and The Board of Trustee of the California State University as Amici Curiae on behalf of
    Defendants and Respondents and Real Parties in Interest and Respondents.
    M. Reed Hopper for Pacific Legal Foundation as Amicus Curiae on behalf of Defendants and Respondents
    and Real Parties in Interest and Respondents.
    Holland & Knight, Amanda Monchamp and Melanie Sengupta for League for California Cities and
    California State Association of Counties as Amici Curiae on behalf of Defendants and Respondents and
    Real Parties in Interest and Respondents.
    Kamala D. Harris, Attorney General, Sally Magnani, Assistant Attorney General, Janill Richards and
    Catherine M. Wieman, Deputy Attorneys General, as Amici Curiae.
    2
    Counsel who argued in Supreme Court (not intended for publication with opinion):
    Susan Brandt-Hawley
    Brandt-Hawley Law Group
    P.O. Box 1659
    Glen Ellen, CA 95442
    (707) 938-3900
    Amrit S. Kulkarni
    Meyers, Nave, Riback, Silver & Wilson
    555 12th Street, Suite 1500
    Oakland, CA 94607
    (510) 808-2000
    3