108OAG64 ( 2023 )


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  • 64                                                  [108 Op. Att’y
    ENVIRONMENT
    NOISE REGULATION – AGRICULTURE – WHETHER “DEER
    CANNONS” ARE EXEMPT FROM MARYLAND’S STATEWIDE
    NOISE REGULATION UNDER THE EXEMPTION FOR
    “AGRICULTURAL FIELD MACHINERY”
    May 17, 2023
    The Honorable Earl F. Hance, President
    Board of County Commissioners of Calvert County
    The Board of County Commissioners for Calvert County has
    asked for our opinion on whether a farmer’s use of a “deer
    cannon”—a propane-powered device that creates an explosive
    sound to frighten deer and other wildlife away from crops—is
    exempt from Maryland’s statewide noise regulation under an
    exemption for “agricultural field machinery.”            COMAR
    26.02.03.02C(2)(c). Based on the language of the regulation as
    well as the history and apparent purpose of the regulation and its
    authorizing statute, we answer this question in the affirmative.
    Provided that the propane cannon is “used and maintained in
    accordance with [the] manufacturer’s specifications,” COMAR
    26.02.03.02C(2)(c), our opinion is that the device, when used for
    its intended purpose to frighten wildlife away from crops, falls
    within the exemption for agricultural field machinery. Neither the
    regulation nor its authorizing statute, however, prohibits a local
    government that is otherwise authorized to regulate noise from
    enacting its own, stricter noise control ordinance or regulation
    restricting the use of propane cannons.
    I
    Background
    A.   Farmers’ Use of Auditory Scare Devices to Protect Crops
    Farmers “ha[ve] been in conflict with wild animals since
    [they] first planted crops in animal habitat,” John D. Harder, A
    Literature Review on Orchard Damage by Deer 15 (1968)
    [hereinafter “Orchard Damage by Deer”] and have long used
    noisemaking devices to scare off pests. “Until the early twentieth
    century,” farmers in England paid “human scarers . . . to pace field
    perimeters, equipped with a wooden rattle or clapperboard, to
    sound a likeness of the shotgun’s sharp retort.” Hayden Lorimer,
    Scaring Crows, 103-2 Geographical Rev. 177, 181 (2013). As
    early as 1932, farmers in the United States began using frightening
    Gen. 64]                                                                  65
    devices called automatic flash guns or carbide guns, which created
    intermittent loud explosions and flashes of light by dripping water
    on carbide and igniting the resulting explosive gas. Orchard
    Damage by Deer at 9; Earl Roy Biehn, Crop Damage by Wildlife
    in California with Special Emphasis on Deer and Waterfowl 48
    (June 1950) (unpublished M.A. thesis, University of the Pacific).
    By 1967, the Maryland Department of Game and Inland Fish
    was supplying farmers with noisemaking scare devices, which
    were considered, at the time, “the most widely used and effective
    method available for preventing damage to crops” by wildlife.
    Committee on Damage to Crops by Birds and Wildlife, Report on
    the Problem of Damage to Agricultural Crops by Wildlife in
    Maryland 11-12 (1967) [hereinafter “1967 Report”]; see also R.K.
    Murton, Man and Birds 306 (1971) (noting that, by 1971, “[n]oise
    machines” for scaring birds away from crops “ha[d] been in vogue
    for ages”). Scare devices included shotguns loaded with exploding
    shells called shell crackers and rope-firecracker assemblies, in
    which firecrackers arranged along a cotton rope would ignite and
    explode at periodic intervals. 1967 Report at 12. The most
    commonly used devices, however, were gas exploders, which
    produced automatically timed explosions. Id.
    “Gas-operated exploders, sometimes referred to as gas or
    propane cannons,”1 “deer cannons,”2 or “bird bangers,” have a
    cylindrical barrel, a spark plug, valves, and a tank of propane gas.
    Hugh Fraser, Using propane-fired cannons to keep birds away
    from vineyards, Ontario Ministry of Agric., Food and Rural Affairs
    (July 2010), https://www.ontario.ca/page/using-propane-fired-
    cannons-keep-birds-away-vineyards. When activated, a valve
    sends propane into the barrel, where the spark plug ignites the gas,
    creating an explosive sound. Id. People have compared the noise
    to the sound of bomb explosions,3 a “loud thunderclap,”4 and
    1
    National Academies of Sciences, Engineering, and Medicine,
    Bird Harassment, Repellent, and Deterrent Techniques for Use on and
    Near Airports 11 (2011).
    2
    See Memorandum from John Norris, County Attorney for Calvert
    County, to the Board of County Commissioners of Calvert County, at 1
    (Aug. 10, 2022) (“Norris Memorandum”).
    3
    John Flink, Sea Gull Solution a Problem for Humans: Noisy
    Cannons Used to Scare Away Birds, Chicago Tribune, Apr. 23, 1998
    (Metro Lake), at 1.
    4
    Gregory B. Hladky, Loud Noise, Big Response: ‘Corn Cannons’
    Scare Birds, but Shatter Nerves, Too, Hartford Courant, Apr. 27, 2015, at B1.
    66                                                        [108 Op. Att’y
    fireworks.5 A single cannon can emit a sound that is 120 or 130
    decibels.6 John Cummings, U.S. Dep’t of Agric., Geese, Ducks
    and Coots 3 (2016) [hereinafter “Geese, Ducks and Coots”]
    (asserting that the devices can emit a 120-decibel sound); Nixalite
    of America, Inc., Wildlife Propane Cannon, https://www.nixalite.
    com/products/wildlife-propane-cannon (last visited May 2, 2023)
    (describing a model that emits a 130-decibel sound). By
    comparison, normal conversation is about 60 decibels, and the
    sound of a gas-powered lawnmower is about 80 to 85 decibels.7
    Propane cannons are considerably louder than many other
    machines used on a farm. The sound of an idling tractor is about
    80 decibels, a typical grain auger (a device used to transport grain
    on a farm) operates at about 95 decibels, and a grain dryer operates
    at about 110 decibels.8 The sound of a tractor “at full load,”
    however, is about 120 decibels—the same volume as many
    propane cannons.9 Today, propane cannons remain “the most
    common scare devices” used to prevent crop damage.10
    5
    David Southwell, North Suburb in Uproar over Bid to Oust
    Seagulls, Chicago Sun Times, Apr 23, 1998, at 1.
    6
    A decibel is “a unit for expressing the relative intensity of sounds
    on a scale from zero for the average least perceptible sound to about 130
    for the average pain level.” Merriam-Webster Dictionary, www.merriam-
    webster.com/dictionary/decibel (last visited May 2, 2023).
    7
    Centers for Disease Control & Prevention, What Noises Cause
    Hearing Loss? (Nov. 8, 2022), https://www.cdc.gov/nceh/hearing_loss/
    what_noises_cause_hearing_loss.html#:~:text=A%20whisper%20is%20
    about%2030,immediate%20harm%20to%20your%20ears.
    8
    U.S Dep’t of Health and Human Servs., How Loud is Too Loud
    on the Farm?, https://www.ncagromedicine.org/pdf/resources/HowLoudis
    TooLoudFarm_Bookmark.pdf (last visited May 3, 2023); David W.
    Smith, Hearing Loss Protection for Agricultural Workers, AgriLife
    Extension, Texas A & M System, at 1, http://agrilife.org/agsafety/files/
    2011/06/HEARING-LOSS-PROTECTION2.pdf.
    9
    See Smith, supra n.8, at 1.
    10
    Jonathan Kays, Maryland Cooperative Extension, Bulletin 354,
    Managing Deer Damage in Maryland, at 8 (updated Feb. 4, 2021)
    [hereinafter     “Managing        Deer     Damage        in     Maryland”],
    https://extension.umd.edu/sites/extension.umd.edu/files/publications/E
    B354_ManagingDeerDamage.pdf; see also C.A. Wyenandt et al.,
    2022/2023 Mid-Atlantic Commercial Vegetable Recommendations, at
    21-22,       https://extension.umd.edu/resource/2022-2023-mid-atlantic-
    commercial-vegetable-production-recommendations (recognizing that
    propane cannons are still used for protecting crops against birds and
    Gen. 64]                                                                67
    B.   Regulation of Noise in Maryland
    “Meaningful governmental regulation aimed at securing a
    quieter environment is a relatively new development.” 4 Frank P.
    Grad, Treatise on Environmental Law § 5.03(2) (2015). In 1972,
    upon finding that “inadequately controlled noise present[ed] a
    growing danger to the health and welfare of the Nation’s
    population,” Congress enacted the Noise Control Act “to deal with
    major noise sources in commerce.” 
    42 U.S.C. § 4901
    (a)(1), (3).
    But Congress acknowledged that “primary responsibility for
    control of noise rest[ed] with State and local governments.” 
    Id.
    § 4901(a)(3).
    That same year, Maryland’s Department of Transportation
    began studying noise pollution related to aviation. Maryland Dep’t
    of Transp., Environmental Noise Act of 1974: Final Report of the
    Noise Pollution Legislation Study 1 (1974) [hereinafter “Final
    Report of the Noise Pollution Legislation Study”]; see S. Res. No.
    102, 1972 Leg., Reg. Sess. Working with several other State
    agencies,11 the Department expanded the study’s scope “to include
    all forms of transportation-generated noise” and developed “a
    legislative proposal” that became the Environmental Noise Act of
    1974. Final Report of the Noise Pollution Legislation Study at 1.
    The resulting statute, now found in Title 3 of the Environment
    Article, recognized that excessive noise could have “adverse
    effects” on Marylanders’ “health, general welfare, [] property,” and
    “quality of life.” Md. Ann. Code, Art. 43, § 822(a), (b) (1971 Repl.
    Vol. & 1974 Supp.). The Legislature thus directed the Department
    of Health and Mental Hygiene to establish noise standards with the
    advice and input of an interagency noise control committee,
    composed of representatives of the Governor’s office and various
    State agencies, and an environmental noise advisory council, made
    deer); Geese, Ducks and Coots at 3 (noting that gas-operated cannons,
    “generally referred to as propane cannons, are commonly used to
    disperse geese . . . from a number of locations, including agricultural
    crops.”); cf. Briggs v. Hughes, 
    316 So. 3d 193
    , 195 (Miss. 2021)
    (characterizing propane cannons as “part of . . . farms’ best agricultural-
    management practices”).
    11
    Cooperating with the Department of Transportation were the
    Departments of Health and Mental Hygiene, Natural Resources, Public
    Safety and Correctional Services, and State Planning. Final Report of
    the Noise Pollution Legislation Study at 1. The Department of
    Agriculture, newly established in 1972, did not participate, and the study
    makes no mention of noise associated with agriculture.
    68                                                   [108 Op. Att’y
    up of five members appointed by the Secretary of Health and
    Mental Hygiene. 
    Id.
     §§ 824, 825, 827, 828.
    In establishing environmental noise standards, the statute
    directed the Department to “take into consideration scientific
    information concerning the volume, frequency, duration and other
    characteristics of noise which may adversely affect public health,
    safety, or general welfare,” and adverse effects such as:
    temporary or permanent hearing loss,
    interference with sleep, speech communication,
    work or other human activities, adverse
    physiological responses or psychological
    distress, adverse effects on animal life,
    devaluation or damage of property, and
    unreasonable interference with the enjoyment
    of life or property.
    Id. § 828(a). The legislation further directed the Department to
    adopt, with input from the noise advisory council, “sound level
    limits” and related regulations “for various categories of land use
    to control noise emanating from activities on private real property,”
    taking into account, “among other things, the residential,
    commercial or industrial nature of the area affected, zoning, the
    nature and source of various kinds of environmental noise, the
    degree of noise reduction achievable through the application of the
    best available technology, and the cost of compliance.” Id.
    § 828(b); see also id. § 824 (directing the Department to
    promulgate regulations).
    On August 6, 1975, the Department of Health and Mental
    Hygiene promulgated the predecessor of the regulation that is the
    subject of your opinion request (and which now appears at
    COMAR 26.02.03).12            The current regulation sets forth
    “Environmental Noise Standards” in COMAR 26.02.03.02.
    Subsection B establishes “general” noise level standards for the
    State, including the allowable “day” and “night” decibels for all
    activities in “industrial,” “commercial,” and “residential” zoning
    12
    The original “Rules and Regulations Governing the Control of Air
    Pollution in the State of Maryland” appeared at COMAR 10.03.45. 2:
    17 Md. Reg. 1189
    -92 (Aug. 6, 1975). The regulation was later recodified
    at COMAR 10.20.01 before moving to COMAR 26.02.03.
    Gen. 64]                                                               69
    districts, as designated by the political subdivisions of the State.13
    In commercial settings, for instance, noise levels generally may not
    exceed 67 decibels during the day and 62 decibels at night.
    COMAR 26.02.03.02B(1). The regulation imposes a lower limit—
    62 decibels during the day and 57 decibels at night for commercial
    settings—for “the emission of prominent discrete tones and
    periodic noises.”14 COMAR 26.02.03.02B(1), (3). But subsection
    C of the regulation contains exemptions to these general
    restrictions, including, as relevant here, that “[t]he provisions of
    this regulation do not apply to . . . [a]gricultural field machinery
    when used and maintained in accordance with manufacturer’s
    specifications[.]” COMAR 26.02.03.02C(2)(c).
    The Environmental Noise Act generally does not limit any
    power that a political subdivision might otherwise have to adopt its
    own noise control ordinances, rules, or regulations, provided they
    are not less stringent than State environmental noise standards,
    sound level limits, and noise control rules and regulations. Md.
    Code Ann., Env’t (“EN”) § 3-105(a). But Calvert County, even
    though it is authorized under a public local law to adopt its own
    noise ordinance, see Calvert County Code of Public Local Laws
    § 13-101 (2010), apparently has not adopted any noise restrictions
    more stringent than the State noise standards, see Calvert County
    Code § 80-1 (adopting as the noise control ordinance for Calvert
    County the State regulations).
    C.        Deer Cannon Use in Calvert County
    Our understanding, based on your opinion request, is that
    Calvert County officials have received complaints from residents,
    some of whom are military veterans with post-traumatic stress
    disorder, about the “disruptive effect” of a soybean farmer’s use of
    a propane cannon causing “loud noises . . . without respite, day or
    night, multiple times per hour.” Letter from Board of County
    13
    COMAR 26.02.03.01B(26) defines a “zoning district” as “a general
    land use category, defined according to local subdivision, the activities
    and uses for which are generally uniform throughout the subdivision.”
    Subsections (a) through (c) of that regulation further define the terms
    “industrial,” “commercial,” and “residential” according to types of land
    use, for any property subject to the regulation that has not been zoned by
    a subdivision as one of these three categories of “zoning districts.”
    14
    “Prominent discrete tone” means “any sound which can be
    distinctly heard as a single pitch or a set of single pitches.” COMAR
    26.02.03.01B(19). “Periodic noise” means “noise possessing a repetitive
    on-and-off characteristic with a rapid rise to maximum and a short decay
    not exceeding 2 seconds.” Id. (17).
    70                                                  [108 Op. Att’y
    Commissioners of Calvert County to Attorney General Brian E.
    Frosh (Aug. 12, 2022); Norris Memorandum at 1. Specifically,
    residents of three households have complained that the cannon
    “[s]ounds like constant gun shot,” which “spook[s] the
    neighborhood dogs and keep[s] [the residents] up all night.”
    Calvert County Health Dep’t, Sanitary Nuisance Complaint
    Investigation (July 25, 2022).
    On July 26, 2022, around 1 p.m., an official with the Calvert
    County Health Department visited the house site closest to the farm
    and heard the cannon blast four times in about twenty minutes.
    Matthew N. Cumers, Director, Calvert County Health Dep’t, Div.
    of Env’t Health, Report of observations made during investigation
    of complaints (July 26, 2022) [hereinafter “Cumers Report”]. The
    official described the noise as “unexpected and annoying” but not
    a “danger to public health or safety.” Id.
    The County Attorney for Calvert County has opined that, in
    his view, a propane cannon—used as the manufacturer intended, to
    scare deer away from crops—qualifies as “agricultural field
    machinery” and is thus exempt from noise regulation under
    COMAR 26.02.03.02C(2)(c).         Norris Memorandum at 2.
    Nonetheless, the County Attorney suggested that you seek our
    opinion.
    II
    Analysis
    To determine whether a farmer’s use of a deer cannon is
    exempt from the statewide noise regulation under the “agricultural
    field machinery” exemption, we must interpret the regulation and
    try to divine the drafters’ intent. See, e.g., Department of Pub.
    Safety & Corr. Servs. v. Howard, 
    339 Md. 357
    , 369 (1995) (noting
    that “the same rules applicable to the interpretation of statutes”
    generally apply to the interpretation of regulations); Huggins v.
    State, 
    479 Md. 433
    , 442 (2022) (recognizing that the goal of
    statutory interpretation is “to understand and implement” the intent
    of the drafters). We do this by considering the text of the
    regulation, as well as the legislative history and apparent purpose
    of the regulation and its authorizing statute. See Lockshin v.
    Semsker, 
    412 Md. 257
    , 275-76 (2010).
    A.   Text of the Regulation
    Our first step is to examine the regulation’s text. See GenOn
    Mid-Atlantic, LLC v. Maryland Dep’t of Env’t, 
    248 Md. App. 253
    ,
    Gen. 64]                                                             71
    270 (2020). The regulation plainly exempts from noise regulation
    “[a]gricultural field machinery when used and maintained in
    accordance with [a] manufacturer’s specifications.” COMAR
    26.02.03.02C(2)(c). But neither the Environmental Noise Act nor
    the statewide noise regulation defines the term “agricultural field
    machinery.” Nor have we been able to locate any judicial opinions
    or administrative decisions from Maryland or any other state
    interpreting this phrase. We thus look to the “ordinary and
    commonly-accepted meaning” of those words. Controller, Anne
    Arundel County v. Pleasure Cove Yacht Club, Inc., 
    334 Md. 450
    ,
    464 (1994) (quoting Scoville Serv., Inc. v. Comptroller, 
    269 Md. 390
    , 395 (1973)).
    To “ascertain the natural and ordinary meaning of” a term, in
    turn, we may “look to dictionary definitions,” Montgomery County
    v. Cochran, 
    471 Md. 186
    , 221 (2020) (quoting Bottini v.
    Department of Fin., 
    450 Md. 177
    , 195 (2016)), “consult[ing] those
    editions (in addition to current editions) of dictionaries that were
    extant at the time of the pertinent legislative enactments,” Minh-Vu
    Hoang v. Lowery, 
    469 Md. 95
    , 120 (2020) (quoting Ali v. CIT Tech.
    Fin. Servs., Inc., 
    416 Md. 249
    , 262 (2010)). “Although dictionary
    definitions do not provide dispositive resolutions of the meaning of
    statutory terms,” Marriott Emps. Fed. Credit Union v. Motor
    Vehicle Admin., 
    346 Md. 437
    , 447 (1997) (citing Morris v. Prince
    George’s County, 
    319 Md. 597
    , 606 (1990)), “dictionaries . . . do
    provide a useful starting point for determining what statutory terms
    mean, at least in the abstract, by suggesting what the legislature
    could have meant by using particular terms,” 
    id.
     (ellipsis in
    original) (quoting 2A Norman J. Singer, Sutherland Statutory
    Construction, § 47.28 (5th ed. 1993 & 1996 Cum. Supp.)). As
    noted above, the regulation at issue here was promulgated in 1975.
    We thus consult dictionaries printed before 1975, as well as current
    editions, to determine the ordinary meaning of “agricultural field
    machinery.”
    According to these sources, “agricultural” means “connected
    with farming”15 or “of, relating to, used in, or concerned
    with agriculture,”16 which is defined as “the science and art of
    farming”17 or “of cultivating the soil, producing crops, and raising
    livestock and in varying degrees the preparation and marketing of
    15
    Webster’s New World Dictionary of the American Language 29 (1966).
    16
    Merriam-Webster Dictionary, https://www.merriam-webster.com/dic
    tionary/agricultural (last visited May 4, 2023).
    17
    Webster’s New World Dictionary of the American Language 29
    (1966).
    72                                                   [108 Op. Att’y
    the resulting products.”18 The definition of “field” includes “an
    open land area free of woods and buildings” and an area of “cleared
    enclosed land,”19 “set off . . . for raising crops or pasturing
    livestock.”20 “Machinery,” meanwhile, is commonly understood
    to mean “machines” or “the working parts of a machine.”21
    “Machine,” in turn, means “a mechanically, electrically, or
    electronically operated device for performing a task,”22 or a “device
    or apparatus consisting of fixed and moving parts that work
    together to perform some function.”23
    The dictionary definitions of these component words, read
    together, suggest that “agricultural field machinery” means
    mechanical devices used in farming and, more specifically, devices
    used in areas that farmers have cleared for raising crops or
    livestock. Although large machinery such as tractors and combine
    harvesters probably come to mind first, the phrase “agricultural
    field machinery” is not limited to those archetypal examples and
    appears broad enough to encompass propane cannons as well.
    After all, these devices consist of multiple parts designed to
    perform the function of emitting sonic blasts at regular intervals
    and, by any rational definition, are “machines” as that term was
    commonly understood in 1975. Moreover, farmers commonly use
    these machines in crop fields to assist with their agricultural
    production by scaring away wildlife that might otherwise damage
    the crops. See Managing Deer Damage in Maryland at 8 (noting
    that “[g]as exploders . . . are the most common scare devices” used
    by farmers for crop protection); see also Wildlife Control Supplies,
    M8 Multi Bang Propane Cannon, https://www.wildlifecontrolsupp
    18
    Merriam-Webster Dictionary, https://www.merriam-webster.com/
    dictionary/agriculture (last visited May 4, 2023).
    19
    Merriam-Webster Dictionary, https://www.merriam-webster.com/
    dictionary/field (last visited May 4, 2023).
    20
    Webster’s New World Dictionary of the American Language 539
    (1966).
    21
    Merriam-Webster Dictionary, https://www.merriam-webster.com/
    dictionary/machinery (last visited May 4, 2023); Webster’s New World
    Dictionary of the American Language 878 (1966).
    22
    Merriam-Webster Dictionary, https://www.merriam-webster.com/
    dictionary/machine (last visited May 4, 2023).
    23
    Black’s Law Dictionary (11th ed. 2019); see also Webster’s New
    World Dictionary of the American Language 878 (1966) (defining
    “machine” to mean, among other things, “a structure consisting of a
    framework and various fixed and moving parts, for doing some kind of
    work”).
    Gen. 64]                                                          73
    lies.com/animal/WCSRJM8.html (indicating that the M8 Multi-
    Bang Cannon “is designed to be fired in an open field” to “disperse
    birds and wildlife from crops, orchards, vineyards” and other
    locations (emphasis added)) (last visited May 4, 2023); Oesco, Inc.,
    Mark 4 Propane Cannon, https://www.oescoinc.com/mark-4-
    propane-cannon.html (indicating that the “Mark 4 Propane
    Cannon” is “ideal for” use “in vineyards, orchards, . . . row crops—
    practically any large, open area with nuisance birds & wildlife”
    (emphasis added)) (last visited May 5, 2023). Propane cannons
    thus appear to fall within the plain meaning of “agricultural field
    machinery.”
    We draw further support for this reading from the fact that the
    Department of Natural Resources (“DNR”) continues to
    recommend the use of propane cannons to deter wildlife from
    agricultural crops.      See DNR, Deer Damage Management
    Techniques, https://dnr.maryland.gov/wildlife/pages/hunt_trap/dd
    mtdeter.aspx (advising “a combination of methods” to deter deer,
    including auditory deterrents such as “gas or propane exploders”)
    (last visited May 4, 2023); DNR, Controlling Conflicts with
    Resident Canada Geese in Maryland, https://dnr.maryland.gov/
    wildlife/Pages/plants_wildlife/ResGeeseProblem.aspx (providing
    contact information for suppliers of propane cannons) (last visited
    May 4, 2023). Although DNR is not the agency responsible for
    promulgating the statewide noise regulation, it was among the
    agencies represented on the Interagency Noise Control Committee
    that provided input on the statewide noise regulations. See
    Interagency Noise Control Committee, 1975 Annual Report 1
    (1976) (listing members of the committee). We thus find it
    significant that this State agency continues to recommend the use
    of propane cannons to support agricultural production. After all,
    these cannons are legal only if they fall within the “agricultural
    field machinery” exemption, as the cannons’ blasts are too loud to
    meet the general noise restrictions, see COMAR 26.02.03.02B, and
    none of the regulation’s other sixteen exemptions—covering such
    things as motor vehicles, emergency operations, construction, and
    air conditioning equipment—encompass propane cannons used to
    deter wildlife from agricultural crops.             See COMAR
    26.02.03.02C(2)(a), (b), and (d) to (q). Thus, DNR’s continued
    recommendation that farmers use propane cannons suggests that
    the devices are commonly understood to be “agricultural field
    machinery” and reenforces our view that this regulatory term
    encompasses propane cannons. See, e.g., Gillespie v. State, 
    370 Md. 219
    , 222 (2002) (“We view the words of a statute . . . in the
    manner in which they are most commonly understood.”).
    74                                                       [108 Op. Att’y
    B.        Legislative History
    To confirm this conclusion or resolve any lingering
    ambiguity, we also consult the legislative history. E.g., Nationstar
    Mortg. LLC v. Kemp, 
    476 Md. 149
    , 170 (2021). But very little
    existed in the first place, and much has been lost to time. The
    General Assembly did not keep a bill file for the 1974 legislation
    that became the Environmental Noise Act.24 And while the
    legislation called for an interagency noise control committee to
    provide input on noise regulations, Md. Ann. Code, Art. 43, § 827
    (1971 Repl. Vol. & 1974 Supp.), we have not been able to locate
    any such input. The committee’s 1974 annual report—and any
    advice the report may have offered about the 1975 noise regulation
    at issue here25—is not available in the State Archives, and we have
    been unable to find a copy anywhere else. Nor have we been able
    to find any advice that the Environmental Noise Advisory Council,
    another creature of the Environmental Noise Act, see Md. Ann.
    Code, Art. 43, § 825, may have offered the Department of Mental
    Health and Hygiene before it promulgated the relevant regulation
    on August 6, 1975.26
    What little legislative history is available indicates that the
    drafters intended to craft an expansive exemption for noise related
    to farming. As initially proposed, the regulation would have
    limited the “agricultural field machinery” exemption to the daytime
    hours of 7:00 a.m. to 10:00 p.m. 2:
    8 Md. Reg. 604
    , 606 (Apr. 16,
    1975). While there is no record documenting the reason for the
    change, the Department consciously deleted the daytime limitation,
    exempting from regulation agricultural field machinery used at any
    24
    Bill files containing legislative history for each House and Senate
    bill were not routinely kept until 1976, see, e.g., Thurgood Marshall State
    Law Library, Guide to Maryland Legislative History Research,
    https://mdcourts.gov/lawlib/research/research-guides/guide-to-md-legis
    lative-history-research (last visited May 4, 2023), and research has
    confirmed that no such file exists for Senate Bill 870, which became the
    Environmental Noise Act of 1974.
    25
    See Interagency Noise Control Committee, 1975 Annual Report 2
    (1976) (referring to “recommendations of the 1974 Annual Report,” but
    failing to elaborate on what those recommendations were).
    26
    The Environmental Noise Advisory Council and the Interagency
    Noise Control Committee were formally eliminated in 2012. See EN
    § 3-403; 2012 Md. Laws, ch. 360. The advisory council “ha[d] not
    existed since” 2005, when the Department of the Environment’s noise
    control program was defunded. Floor Report, Senate Educ., Health,
    & Env’t Affairs Comm., H.B. 190, 2012 Leg., Reg. Sess., at 2.
    Gen. 64]                                                                75
    time, day or night. See 26.02.03.02.C(2)(c). And although the
    applicable hours do not illuminate whether the drafters intended the
    exemption to encompass propane cannons, this detail does suggest
    that the drafters intended to impose fewer restrictions on noise
    related to farming than on noise related to other activities, such as
    lawn care, snow removal, blasting operations, and pile-driving—
    all activities that the drafters exempted from noise regulation
    during daytime hours only. See 2:
    17 Md. Reg. 1191
     (Aug. 6,
    1975).27
    We note, too, that drafters of the noise regulation—and its
    exemption for “agricultural field machinery”—would likely have
    been aware of noisemaking scare devices like propane cannons,
    given that the State itself had supplied scare devices to farmers and
    that, by the late 1960s, the devices were considered “the most
    widely used and effective method available for preventing damage
    to crops” by wildlife. See 1967 Report at 12. Moreover, the
    capacity for such devices to produce sounds that disturbed nearby
    residents was well-established by 1975. In a 1966 resolution
    calling for the study of crop damage by wildlife in Maryland and
    the use of noisemaking scare devices, members of the House of
    Delegates recognized that “the use of explosives regularly
    detonated and the device colloquially referred to as a ‘carbide
    cannon’” was “causing the loss of use and enjoyment of the
    property in the vicinity of such devices.” H. Res. 93, 1966 Leg.,
    Reg. Sess., reprinted in 1967 Report at iii; see also 1967 Report at
    24 (recognizing that noisemaking scare devices caused “undue
    annoyance in populated areas”). Notwithstanding these facts, less
    than a decade later, drafters of the statewide noise regulation
    crafted a broadly worded exemption for “agricultural field
    machinery,” without limitation (other than the caveat that the
    machinery be “used and maintained in accordance with [the]
    manufacturer’s specification”). COMAR 26.02.03.02C(2)(c).
    This suggests that the drafters intended the exemption to
    encompass propane cannons, many of which are no louder than a
    tractor at full load.
    We recognize that, unlike tractors and other farm equipment,
    noise is the very purpose of a propane cannon, not merely a
    byproduct of its use. And unlike the drone of a tractor, a cannon’s
    blast is intermittent and intentionally startling. As the regulation
    27
    The current version of the regulation limits four other exemptions
    to certain hours of the day: exemptions for sporting and entertainment
    events, target shooting (in certain counties), trash collection, and marina
    equipment used to move boats. COMAR 26.02.03.02C(2)(j), (o), (p),
    (q).
    76                                                  [108 Op. Att’y
    itself seems to implicitly recognize, discrete tones may be more
    irritating than a continual drone. See COMAR 26.02.03.02B(1),
    (3) (imposing lower volume limits for “prominent discrete tones
    and periodic noises” than for other noise). But the regulation
    exempts “agricultural field machinery” broadly, without
    distinguishing between devices that emit a drone and those that
    produce “prominent discrete tones.” Moreover, because propane
    cannons were (and remain) common, and because the drafters
    nonetheless adopted such a sweeping exemption without limiting
    its scope to only certain types of agricultural field machinery, we
    think it more likely the drafters intended the exemption for such
    machinery to include propane cannons.
    To be clear, we do not in any way mean to minimize the very
    real hardship that deer cannons may cause to some individuals,
    particularly military veterans with post-traumatic stress disorder
    (“PTSD”), for whom loud noises may “bring up trauma memories”
    and “intense anxiety and fear.” Matthew Moeller, How Your
    Fireworks May Affect America’s Veterans, June 27, 2022,
    https://www.va.gov/hines-health-care/stories/how-your-fireworks
    -may-affect-americas-veterans/ (quoting psychologist Annie Tang).
    The General Assembly has recently enacted legislation to help
    veterans with PTSD and to offer more support for veterans’ mental
    health generally. See 2022 Md. Law, ch. 731 (establishing a fund
    to support the study of alternative therapies for PTSD and traumatic
    brain injuries in veterans); 2021 Md. Laws, ch. 137 (requiring the
    Department of Health to provide veterans “mental health first aid”).
    But these laws did not amend, and do not bear on our interpretation
    of, the exemption for “agricultural field machinery” in the
    statewide noise regulation, the plain language of which suggests
    that deer cannons are exempt from that regulation.
    C.   Purpose of the Noise Regulation and Authorizing Statute
    We next consider whether this reading is consistent with the
    apparent purpose of the regulation and its authorizing statute. See
    Schmerling v. Injured Workers’ Ins. Fund, 
    368 Md. 434
    , 444
    (2002) (defining a statutory term by considering, among other
    things, “the express and implied purpose of the statute”). In
    passing the Environmental Noise Act, the General Assembly found
    that “people of this State have a right to an environment free from
    noise that may jeopardize their health, general welfare, and
    property, or that degrades their quality of life.” Md. Ann. Code,
    Art. 43, § 822(a). The Legislature referenced the “substantial body
    of knowledge . . . concerning the adverse effects of excessive
    noise” and asserted that “[t]his knowledge should be used to
    Gen. 64]                                                            77
    establish environmental noise standards which [would] protect the
    public health and general welfare with an adequate margin of
    safety.” Id. § 822(b), (c). But the Legislature also indicated that
    noise standards should restrict only “unreasonable interference
    with the enjoyment of life or property,” id. § 828(a) (emphasis
    added), and that regulations should take into account “the nature
    and source of various kinds of environmental noise,” the “nature of
    the area affected,” “the degree of noise reduction achievable
    through the application of the best available technology, and the
    cost of compliance.” Id. § 828(b)(3).
    Drafters of the statewide noise regulation similarly
    recognized that “noise above certain levels is harmful to the health
    of humans” and that “one’s well-being can be affected by noise
    through loss of sleep, speech interference, hearing impairment, and
    a variety of other psychological and physiological factors.”
    COMAR 26.02.03.02A(1). But the drafters also acknowledged the
    need to establish ambient noise standards that “provide margins of
    safety” while giving “due consideration to technical and economic
    factors.” Id.
    It thus appears that the purpose of the Environmental Noise
    Act and related regulation is not to eliminate all bothersome noise.
    Rather, the statute and regulation aim to strike a balance between,
    on the one hand, protecting Marylanders from excessive noise that
    unreasonably interferes with their health and quality of life and, on
    the other hand, permitting noise that, while irritating, is a necessary
    part of modern life. The regulation strikes that balance by setting
    forth general noise limits but carving out several exemptions,
    including the one for the use of “agricultural field machinery.”
    The Environmental Noise Act also recognizes that the
    standards set forth in the statewide noise regulation are merely the
    outer limits on noise control in Maryland; “counties retain
    whatever powers they ha[ve] to regulate noise,” Letter from
    Kathryn M. Rowe, Assistant Attorney General, to Del. Terri L.
    Hill, at 2 (Feb. 1, 2016) (“Hill Letter”), provided that any local
    ordinances or regulations are not “less stringent” than the statewide
    standards, EN § 3-105(a)(2); see also COMAR 26.02.03.00
    (recognizing that the Environmental Noise Act “allows political
    subdivisions to adopt environmental noise standards”). To be
    clear, “[t]he power of political subdivisions to regulate noise does
    not come from the Environment Article, but from other sources,”
    Letter from Kathryn M. Rowe, Assistant Attorney General, to
    Delegates James E. Malone, Jr., and Elizabeth Bobo, at 2 (Mar. 22,
    78                                                      [108 Op. Att’y
    2013), such as the Express Powers Act,28 or public local law, see,
    e.g., Calvert County Code of Public Local Laws § 13-101 (2010)
    (“Subject to § 3-105 of the Environment Article . . . the [Calvert]
    County Commissioners may enact an ordinance that . . . [a]dopts
    environmental noise standards, sound level limits, and noise
    controls as necessary to protect the public health, the general
    welfare, and property . . . .”). Although it is beyond the scope of
    this opinion to survey every local jurisdiction to determine whether
    all of them have been granted the power to adopt noise ordinances,
    many clearly have that authority.
    The fact that the State regulation does not preempt stricter
    regulation by local jurisdictions is important. As some lawmakers
    have observed, the statewide standards “provide a degree of
    uniformity across Maryland,” but many conflicts surrounding noise
    involve matters of local concern. Floor Report, Senate Educ.,
    Health, & Env’t Affairs Comm., H.B. 190, 2012 Leg., Reg. Sess.,
    at 1 (noting that “noise violations are often a result of local land use
    decisions”).29 Thus, another purpose of the statute and related noise
    regulation is to set forth basic statewide noise standards, while
    preserving whatever powers local governments have to impose more
    restrictive rules should local conditions call for them.30
    28
    See Md. Code Ann., Local Gov’t § 10-206(a) (authorizing a charter
    county to “pass any ordinance, resolution, or bylaw” that is “not
    inconsistent with State law” and “may aid in maintaining the peace, good
    government, health, and welfare of the county”); Hill Letter, at 2
    (recognizing that this statutory authority “would be adequate to allow
    charter counties to set their own environmental standards, sound level
    limits, and noise control rules”).
    29
    House Bill 190, among other things, specified that local
    governments adopting their own noise regulations should take into
    account the same factors that State regulators must consider (including
    the nature of an area affected by noise, and the nature and source of a
    noise). 2012 Md. Laws, ch. 360, § 1 (amending EN § 3-401).
    30
    We note that § 5-403 of the Courts and Judicial Proceedings Article,
    which offers farmers some protection from nuisance actions, also does
    not prohibit local governments from enacting noise control laws that are
    more stringent than the statewide standards. Section 5-403 expressly
    provides that a farmer must comply “with applicable federal, State, and
    local health, environmental, zoning, and permit requirements” in order
    to be immune from suits for nuisance or “private action[s]” alleging that
    an agricultural operation “interferes . . . with the use or enjoyment of
    other property.” 
    Md. Code Ann., Cts. & Jud. Proc. § 5-403
    (c) (emphasis
    added) (providing further that immunity requires the agricultural
    operation to have “been under way for a period of 1 year or more” and
    that the operation not be “conducted in a negligent manner”).
    Gen. 64]                                                             79
    Ultimately, we think that construing the “agricultural field
    machinery” exemption to encompass propane cannons is consistent
    with these purposes of the statewide noise regulation and its
    authorizing statute. Although the noise from propane cannons can
    undoubtedly be “unexpected and annoying,” Cumers Report,
    farmers have long used auditory scare devices in agriculture, see
    supra Part I.A, and neither the statute nor the regulation aims to
    eliminate all disruptive noises. Moreover, the use of propane
    cannons seems most likely to lead to conflict in more populated
    areas. See, e.g., Deer Damage Management Techniques (advising
    against using noisemaking scare devices “in suburban or residential
    areas out of consideration for neighbors”); Oesco, Inc., Mark 4
    Propane Cannon, https://www.oescoinc.com/mark-4-propane-
    cannon.html (indicating that one propane cannon “will protect
    approximately 1 to 5 acres”). It thus makes sense that drafters of
    the regulation would generally allow farmers to use propane
    cannons, knowing that local regulators could potentially curb the
    cannons’ use if they were unreasonably interfering with residents’
    quality of life in specific parts of the State. See, e.g., Deer Damage
    Management Techniques (noting that the use of auditory scare
    devices may violate local noise ordinances). Indeed, one county
    has already enacted an ordinance that imposed stricter limits on
    deer cannons than the default State regulation. See Baltimore
    County Code §§ 1A01.5, 1A03.8, 1A05.6, 1A08.7, 1A09.8
    (banning, during the hours from 10 p.m. to sunrise, the use of “an
    air cannon or similar device that releases a loud shotgun-like blast
    within 500 feet of an adjacent residential dwelling”).31 Calvert
    County, which has express statutory authority to enact its own
    noise ordinance, see Calvert County Code of Public Local Laws
    § 13-101 (2010), could follow suit, if it so chooses.32
    31
    These ordinances, enacted in 2017, automatically expired two years
    later. Id. §§ 1A01.5, 1A03.8, 1A05.6, 1A08.7, 1A09.8 (editor’s notes).
    As far as we can tell, then, they are no longer in effect.
    32
    In the memorandum submitted along with your opinion request, the
    County Attorney for Calvert County noted that local governments have
    the option of enforcing statewide noise standards (a task that the
    Department of the Environment no longer performs) and that, in his
    view, the agricultural field machinery exemption is “mandatory.” Norris
    Memorandum at 1 n.8; see also 2012 Md. Laws, ch. 360 (amending EN
    § 3-403 to delete language requiring the Department of the Environment
    to enforce noise standards and to add language providing that “[a]
    political subdivision may enforce” them). We agree that a political
    subdivision, exercising its option to enforce the statewide standards as
    written, must enforce all related exemptions, including the one for
    agricultural field machinery. But a political subdivision exercising its
    80                                                      [108 Op. Att’y
    III
    Conclusion
    For the reasons set forth above, it is our opinion that a
    farmer’s operation of a propane cannon, when “used and
    maintained in accordance with [the] manufacturer’s specifications”
    to frighten wildlife away from crops, is exempt from the statewide
    noise regulations under the exemption for “agricultural field
    machinery.” COMAR 26.02.03.02C(2)(c). We think this
    construction is most consistent with the plain language of the
    regulation and the history and apparent purpose of the regulation
    and its authorizing statute. The “agricultural field machinery”
    exemption does not, however, preclude a county or municipality
    that is otherwise authorized to regulate noise from enacting its own,
    stricter noise control ordinance or regulation to address concerns
    about the noise from propane cannons.
    Anthony G. Brown
    Attorney General of Maryland
    Rachel A. Simmonsen
    Assistant Attorney General
    Michael S. Steadman, Jr.
    Assistant Attorney General
    Patrick B. Hughes
    Chief Counsel, Opinions and Advice
    authority to adopt and enforce its own noise control law need not adopt
    and enforce that exemption; the only relevant restriction is that a local
    government may not enact more lenient noise control standards than
    those imposed by the State. See EN § 3-105(a) (making clear that State
    law “does not limit the power of a political subdivision to adopt noise
    control ordinances, rules, or regulations,” provided that any local law is
    not “less stringent than the [statewide] environmental noise standards,
    sound level limits, and noise control rules and regulations” (emphasis
    added)). Although the public local law authorizing Calvert County to
    regulate noise provides that the County’s power to adopt noise
    regulations is “subject to” § 3-105 of the Environment Article, that just
    means that the County cannot enact standards more lenient that those
    adopted under State law, as the State law itself provides that it does not
    preclude local jurisdictions with authority from adopting more stringent
    requirements.