Street v. Weyerhaeuser Co. ( 2017 )


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  •                                                         This opinion was filed for record
    at     &:OOaJ\A      on   -Altff LL\ 2Pl1
    . :(\Q[
    \.'MY"     .SUSAN L. CARLSON
    -~ SUPREMiCOURTCLERK
    IN TI-IE SUPREME COURT OF THE STATE OF WASHINGTON
    ROGER A. STREET,
    Respondent,                 NO. 93984-5
    v.
    ENBANC
    WEYERHAEUSER COMPANY,
    Petitioner.                              AUG 1 0 2017
    Filed ----'-----=..:::__:_:_-
    STEPHENS, J.-Weyerhaeuser Company, Roger A. Street's former employer,
    challenges Street's award of industrial insurance benefits for his low back condition, a
    claimed occupational disease. An "occupational disease" is a disease that "arises
    naturally and proximately out of employment."            RCW 51.08.140.       In Dennis v.
    Department of Labor & Industries, 
    109 Wash. 2d 467
    , 477, 
    745 P.2d 1295
    (1987), this
    court held that a worker seeking benefits for an occupational disease must present expert
    medical testimony that the disease "arise[s] 'proximately"' out of employment.
    Weyerhaeuser argues that in light of Dennis, such a worker must also present expert
    medical testimony that the disease "arises naturally" out of employment.
    Street v. Weyerhaeuser Company, 93984-5
    The Court of Appeals rejected Weyerhaeuser's argument, holding that neither
    Dennis nor any other appellate decision requires Street to present expert medical
    testimony to show that his back condition "arose naturally" from employment. Because
    there was medical testimony supporting the "arises proximately" requirement and lay
    testimony supporting the "arises naturally" requirement, the appeals court held that
    Street proved his low back condition is an occupational disease and affirmed the jury
    award of benefits. We affirm the Court of Appeals.
    BACKGROUND FACTS AND PROCEDURAL HISTORY
    Street worked for Weyerhaeuser or its subsidiary (Norpac) his entire career. In
    1991, Street began working in one of Norpac's paper mills, where he held various
    positions for the next 20 years. Although Street had back problems prior to working in
    the paper mill, he did not find the problems disabling until he was injured at the mill in
    2011. More than one year later, Street applied for workers' compensation benefits due
    to that injury. The Department of Labor and Industries (Department) treated the
    application as an injury claim and denied it as untimely.
    Later that year, the Department affirmed the denial and sent Street a separate
    letter stating that the claim was for an injury, not an occupational disease. Compare
    RCW 51.28.050 (worker must file injury claim within one year of the date on which
    the injury occurred), with RCW 51.28.055(1) (worker must file occupational disease
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    Street v. Weyerhaeuser Company, 93984-5
    claim within two years of the date the worker had notice of the occupational disease or
    of the ability to file a claim for disability benefits). Street appealed the Department's
    order and letter to the Board of Industrial Insurance Appeals (Board), clarifying that he
    intended to file an occupational disease claim. Weyerhaeuser moved for an order
    granting summary judgment and dismissing Street's appeal. An industrial appeals
    judge granted Weyerhaeuser partial summary judgment, dismissing Street's claim as
    untimely to the extent he alleged an injury, but directing the case to go forward on an
    occupational disease theory.
    The industrial appeals judge conducted hearings, at which Street, his family
    members, his supervisor, and three medical experts testified.
    Street testified that his duties as an assistant winder operator included placing
    cores-dense cardboard at the center of a paper roll-into the winder of the paper
    machine so that the machine could produce individual paper rolls. His duties also
    included monitoring paper machines, repairing broken machines, "manhandling" paper
    rolls by grabbing and pushing the core of the roll, bending over to sand cores, and
    tacking bar codes onto the finished paper rolls. The paper rolls were approximately 40
    to 50 inches in diameter and weighed on average 1,000 pounds. The cores, on which
    the rolls were placed, weighed on average 2 to 10 pounds. Street worked 12-hour shifts
    with few breaks, if any. Some of Street's work became automated over the last 10
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    Street v. Weyerhaeuser Company, 93984-5
    years, and during the last couple of years, Street worked in a less demanding monitoring
    role about 30 percent of the time.
    Richard T. Moore, Street's supervisor of two to five years, gave slightly different
    testimony regarding Street's role. Moore testified that Street held the less demanding
    monitoring role about 75 percent of the time, that Street sat approximately 20 percent
    of the time as an assistant winder operator, and that workers typically had help
    manhandling the paper rolls, which might happen Oto 12 times a day.
    Dr. Patricia Peterson, Street's primary care physician of 20 years, testified that
    she was familiar with the nature of Street's work "[t]o some degree" and described his
    role in the paper mill as a "very heavy job, ... a moving job, ... [not] just a sit around
    and watch things go job." Clerk's Papers (CP) at 313,315,319,321. She testified that
    she diagnosed Street with chronic low back pain related to degenerative arthritis and
    degenerative disease of the spine, which can occur over time from repetitive use.
    Although on Street's short-term disability claim form she had checked a box indicating
    that the condition was not work related, she later testified on a more probable than not
    basis that the kind of work Street did, as opposed to everyday wear and tear of daily
    living, at least in part caused Street's low back condition because he used "a lot of his
    body weight" and his "abdominal muscles" in manhandling paper rolls. Id at 322-23,
    326. Dr. Peterson acknowledged that even though Street had come in with complaints
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    Street v. Weyerhaeuser Company, 93984-5
    of low back pain unrelated to work (e.g., moving furniture, doing yard work), the
    repetition of handling paper rolls was a factor contributing to Street's low back
    condition.
    Dr. Yuri Tsirulnikov, an osteopathic physician who treated Street five to six
    times, testified that Street's work more probably than not contributed to his low back
    condition, though he could not say to "what extent" it contributed. 
    Id. at 362,364,
    367-
    68, 371. He indicated that Street's weight, genetics, and "probably some other physical
    activities that he did at home" also contributed to Street's low back condition. 
    Id. at 384.
    Dr.   Thomas Rosenbaum,        a neurosurgeon who         examined Street at
    Weyerhaeuser's request, opined that Street's work did not proximately cause his low
    back condition. He diagnosed Street with lumbar spondylosis and degenerative disc
    disease, and testified that genetics and age are the main factors contributing to these
    conditions. In his opinion, Street's physical exertion at work contributed to his low
    back condition "maybe ... two or three percent," if at all. 
    Id. at 431-32.
    At the conclusion of the proceedings, the industrial appeals judge issued a
    proposed order and decision reversing the Department's denial of benefits.
    Weyerhaeuser petitioned the full Board for review.        The full Board affirmed the
    Department's denial of benefits, but directed the Department to find that Street filed an
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    Street v. Weyerhaeuser Company, 93984-5
    occupational disease claim that was rejected because he failed to prove his low back
    condition arose "naturally and proximately" out of distinctive conditions of his
    employment. 
    Id. at 49,
    54-55.
    Street appealed the Board's order to Cowlitz County Superior Court.
    Weyerhaeuser moved for judgment as a matter of law on the ground that Street failed
    to present expert medical testimony that his low back condition "arose naturally" out of
    distinctive conditions of his employment. The superior court denied the motion and
    sent the case to trial. The jury found that Street's back condition is an occupational
    disease that arose "naturally and proximately" out of the distinctive conditions of his
    employment. 
    Id. at 532.
    Based on the verdict, the superior court reversed the Board's
    order and remanded to the Department with directions to accept Street's occupational
    disease claim. 
    Id. at 534-35.
    Weyerhaeuser appealed to Division Two of the Court of Appeals, which
    transferred the matter to Division One of the Court of Appeals. Order Transferring
    Cases, Street v. Weyerhaeuser Co., No. 48559-1-II (Wash. Ct. App. Aug. 16, 2016). In
    an unpublished decision, the Court of Appeals affirmed, holding that Street was not
    required to present medical testimony to satisfy the "arises naturally" requirement, and
    that the evidence was sufficient to support a finding that Street's back condition
    qualifies as an occupational disease. Street v. Weyerhaeuser Co., No. 75644-3-1, slip
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    Street v. Weyerhaeuser Company, 93984-5
    op. at 1, 4, 7 (Wash. Ct. App. Nov. 28, 2016) (unpublished), http://www.courts.
    wa.gov/opinions/pdf/756443.pdf.
    Weyerhaeuser then filed a petition for review in this court, which we granted.
    Street v. Weyerhaeuser Co., 
    187 Wash. 2d 1025
    , 
    391 P.3d 457
    (2017).
    ANALYSIS
    The Industrial Insurance Act (IIA), Title 51 RCW, provides "sure and certain
    relief for workers, injured in their work." RCW 51.04.010. Workers "who suffer[]
    disability from an occupational disease in the course of employment" are entitled to
    "the same compensation benefits" as injured workers. RCW 51.32.180. In the present
    case, Street alleges that his chronic low back condition is an occupational disease. CP
    at 57.
    "'Occupational disease' means such disease . . . as anses naturally and
    proximately out of employment." RCW 51.08.140. In Dennis, 
    109 Wash. 2d 467
    , this
    court discussed the requirements for such a claim. "Arises proximately" means that
    employment conditions "'must be the proximate cause of the disease ... so that the
    disease would not have been contracted but for the [employment] condition.'" 
    Id. at 477
    (footnote omitted) (quoting Simpson Logging Co. v. Dep 't of Labor & Indus., 32
    Wn.2d 472,479,202 P.2d 448 (1949)). This "causal connection ... must be established
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    Street v. Weyerhaeuser Company, 93984-5
    by competent medical testimony which shows that the disease is probably, as opposed
    to possibly, caused by the employment." 
    Id. "Arises naturally"
    requires a worker to
    establish that his or her occupational disease came about as a matter of course
    as a natural consequence or incident of distinctive conditions of his or her
    patiicular employment. The conditions need not be peculiar to, nor unique to,
    the worker's particular employment. Moreover, the focus is upon conditions
    giving rise to the occupational disease ... and not upon whether the disease
    itself is common to that particular employment. The worker, in attempting to
    satisfy the "naturally" requirement, must show that his or her particular work
    conditions more probably caused his or her disease ... than conditions in
    everyday life or all employments in general; the disease ... must be a natural
    incident of conditions of that worker's particular employment. Finally, the
    conditions causing the disease ... must be conditions of employment, that is,
    conditions of the worker's particular occupation as opposed to conditions
    coincidentally occurring in his or her workplace.
    
    Id. at 481.
    Although the court in Dennis discussed what a worker must prove to
    demonstrate a disease "arises naturally" out of employment conditions, it did not
    specifically address whether expert medical testimony is required to prove it. That issue
    is now before us.
    I.     The "Arises Naturally" Requirement Need Not Be Established by
    Expert Medical Testimony
    As noted, to satisfy the "arises naturally" requirement, a worker must prove
    that his or her occupational disease came about as a natural consequence of
    distinctive employment conditions. 
    Id. Weyerhaeuser contends
    that whether a
    disease "arises naturally" from distinctive conditions of employment constitutes an
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    Street v. Weyerhaeuser Company, 93984-5
    issue of medical causation that must be proved through expert medical testimony.
    Pet. for Review at 8, 19. Street counters that while the "arises naturally" requirement
    presents an issue of general causation, it does not present an issue of medical
    causation requiring expert testimony. Suppl. Br. of Resp't at 2. Rather, it is a
    causation issue pure and simple; as with most factual causation determinations, it
    does not require expert opinion. 
    Id. at 5;
    Br. ofResp't at 12-13.
    We believe the remedial nature of the IIA, the standard governing the need
    for expert testimony, and our case law all support Street's argument. We discuss
    each of these reasons more fully below.
    a. The IIA Is Broadly Construed in Favor of Workers
    This court has consistently held that because the IIA "is remedial in nature,"
    it must be "liberally construed in order to achieve its purpose of providing
    compensation to all covered employees injured in their employment, with doubts
    resolved in favor of the worker." 
    Dennis, 109 Wash. 2d at 470
    . "With this principle
    in mind," 
    id., both the
    legislature and this court have expanded occupational disease
    coverage under the IIA.      The trend toward liberal coverage supports Street's
    argument that a worker need not present expert medical testimony to prove an
    occupational disease "arises naturally" from employment.
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    Street v. Weyerhaeuser Company, 93984-5
    Dennis is the leading case on occupational disease. There, this court held that
    the "historical development of occupational disease coverage in Washington"
    supports the conclusion that a preexisting condition exacerbated by work comes
    within the definition of an "occupational disease." 
    Id. at 472.
    This court explained
    that at the time the IIA was enacted, there was "no coverage for disability resulting
    from    occupational   disease[,]   only    injuries   sustained   performing   certain
    extrahazardous work." 
    Id. The legislature
    subsequently "passed the first law
    providing compensation for disability resulting from certain enumerated diseases,"
    including "specific conditions resulting from repetitive work activities." 
    Id. at 473.
    Eventually, the legislature "again broadened coverage by eliminating the list of
    enumerated compensable diseases, and enacting the present definition of
    occupational disease," although compensation was available only for extrahazardous
    employment. 
    Id. Finally, the
    legislature eliminated the extrahazardous employment
    requirement and "provided coverage for disability resulting from occupational
    disease in all employment." 
    Id. This court
    summarized, "From 'no coverage' to the
    present broad definition of occupational disease, the Legislature has repeatedly and
    consistently provided expanded coverage for disability resulting from occupational
    disease." 
    Id. at473-74. This
    court concluded that it was a natural next step to expand
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    Street v. Weyerhaeuser Company, 93984-5
    coverage to disabilities resulting from "work-related aggravation of ... preexisting
    nonwork-related diseases." 
    Id. at 474.
    In addition to expanding coverage, this court has at least in two instances
    relaxed the worker's burden of proof for an occupational disease claim. First, in
    Sacred Heart Medical Center v. Carrado, 
    92 Wash. 2d 631
    , 632-33, 
    600 P.2d 1015
    (1979), this court held that the medical testimony was sufficient to support the jury's
    finding that a nurse had contracted hepatitis as a result of her employment even
    though the medical testimony indicated that it is nearly impossible to pinpoint the
    source of the disease.    In so holding, this court stated that while "the causal
    connection between a [worker's] physical condition and his employment must be
    established by" medical testimony, our cases do not require a medical opinion on
    "the ultimate issue" in every instance. 
    Id. at 636.
    Rather, "[i]t is sufficient if the
    medical testimony shows the causal connection." 
    Id. In other
    words, it is sufficient
    if "a reasonable person can infer" from the medical testimony, in conjunction with
    lay testimony, "that the causal connection exists." 
    Id. at 637.
    This suggests there
    are no "magic words" for proving the issue of medical causation. Indeed, in later
    describing its holding, this court stated, "Sacred Heart does not require each [worker
    claiming] occupational disease coverage to prove an increased risk of disease-based
    disability due to conditions of his or her particular employment, but instead eases
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    Street v. Weyerhaeuser Company, 93984-5
    the burden of proof requirement." 
    Dennis, 109 Wash. 2d at 482
    (second emphasis
    added).
    Second, m interpreting the "arises naturally" requirement, this court
    specifically rejected a lower court's more stringent definition.        
    Id. at 478-79
    (rejecting Dep't of Labor & Indus. v. Kinville, 
    35 Wash. App. 80
    , 
    664 P.2d 1311
    (1983)). "Dennis relaxed the requirements of' Kinville, "which required the worker
    to prove 'that the conditions producing his disease are peculiar to, or inherent in, his
    particular occupation."' Kaiser Alum. & Chem. Corp. v. McDowell, 
    58 Wash. App. 283
    , 286-87, 
    792 P.2d 1269
    (1990) (quoting 
    Kinville, 35 Wash. App. at 87
    ). In Dennis,
    this court held that "[t]he conditions need not be peculiar to, nor unique to, the
    worker's particular 
    employment." 109 Wash. 2d at 481
    . Instead, they need only be
    "distinctive" conditions "of the worker's particular occupation as opposed to
    conditions coincidentally occurring" in the workplace. 
    Id. Both the
    legislature's amendments to and this court's decisions interpreting
    the occupational disease statute evidence a trend toward expanded coverage and a
    more relaxed burden of proof. Allowing a worker to prove the "arises naturally"
    requirement without the necessity of medical testimony aligns with this trend.
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    Street v. Weyerhaeuser Company, 93984-5
    b. Expert Medical Testimony Is Necessary Only for Issues of Medical
    Causation, and the "Arises Naturally" Requirement Is Not Such an
    Issue
    In determining whether the "arises naturally" requirement must be proved
    through expert medical testimony, it is helpful to consider in what circumstances
    expert testimony is generally useful. "The admissibility of expert testimony in
    Washington is governed by" Evidence Rule (ER) 702. Reese v. Stroh, 
    128 Wash. 2d 300
    , 305, 
    907 P.2d 282
    (1995). That rule provides that "[i]f scientific, technical, or
    other specialized knowledge will assist the trier of fact to understand the evidence
    or to determine a fact in issue," a qualified expert "may testify thereto in the form of
    an opinion." ER 702. With regard to expert medical testimony, the "general rule"
    is that
    expert medical testimony is required on only those matters "strictly
    involving medical science". The basic question is whether the particular fact
    sought to be proved is such as is "observable by [a layperson's] senses and
    describable without medical training".
    Smith v. Shannon, 
    100 Wash. 2d 26
    , 33, 
    666 P.2d 351
    (1983) (matters involving
    medical science include "the nature of the harm which may result and the probability
    of its occurrence" because "[o]nly a physician ... is capable of judging what risks
    exist and their likelihood of occurrence" (alteration in original) (citation omitted)
    (quoting 2 JOHN HENRY WIGMORE, EVIDENCE IN TRIALS AT COMMON LAW§ 568, at
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    Street v. Weyerhaeuser Company, 93984-5
    779 (rev. 1979); Bennett v. Dep 't of Labor & Indus., 
    95 Wash. 2d 531
    , 533, 
    627 P.2d 104
    (1981))).
    In the context of occupational disease claims, matters involving medical
    science include the "'cause and extent"' of the disability. Eyer v. Dep't ofLabor &
    Indus., l Wn.2d 553, 555, 
    96 P.2d 1115
    (1939) (quotingAtl. Ref Co. v. Allen, 
    1939 OK 116
    , 
    185 Okla. 194
    , 195, 90 P .2d 659); see also Hoff v. Dep 't ofLabor & Indus.,
    198 Wash. 257,266, 
    88 P.2d 419
    (1939) ("[U]pon a medical question regarding the
    nature and effect of a particular ailment ... those who are versed in the science of
    medicine are better able than are we to form a true and accurate opinion.").
    Weyerhaeuser contends that the "arises naturally" requirement is an issue of
    medical causation requiring expert medical testimony that "the work activities at
    Weyerhaeuser were distinctive, compared to activities that are common to
    employment generally and daily life, when viewed as a cause of lumbar
    spondylosis." Br. of Appellant at 19. We find this argument unavailing. "Arises
    proximately" means that the employment conditions must be the proximate cause of
    the disease. Dennis, l 09 Wn.2d at 477. "Arises naturally" means that the conditions
    of a worker's particular employment are distinctive, i.e., different from,
    employments in general or activities of daily living. 
    Id. at 481.
    The first requirement
    involves an issue of medical causation, but the second requirement pertains to
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    Street v. Weyerhaeuser Company, 93984-5
    observable job activities. See, e.g., City ofBremerton v. Shreeve, 
    55 Wash. App. 334
    ,
    340 n.5, 
    777 P.2d 568
    (1989) ("The 'naturally' requirement ... addresses the work
    connection ... , while the 'proximately' requirement is addressed by the 'but for'
    test.").
    Viewing the requirements this way explains why the court in Dennis explicitly
    stated only that expert medical testimony is necessary for the "arises proximately"
    requirement. 
    See 109 Wash. 2d at 4
    77. Medical professionals specialize in diagnosing
    patients' conditions, not in familiarizing themselves with various job duties. Street
    aptly notes that many treating physicians would balk at any requirement that they
    "become experts as to job duties that exist in all employments in general, or testify
    as to what constitutes activities of daily living, versus distinctive job duties." Suppl.
    Br. of Resp't at 5. Amicus Washington State Association for Justice Foundation
    further observes, "[A] medical professional has no particular qualifications that
    would help the trier of fact to determine whether the conditions of a worker's
    particular employment are distinctive." Br. of Amicus Curiae Wash. State Ass'n for
    Justice Found. at 13; see also Wash. Supreme Court oral argument, Street v.
    Weyerhaeuser Co., No. 93984-5 (June 13, 2017), at 5 min., 07 sec. through 6 min.,
    00 sec., video recording by TVW, Washington State's Public Affairs Network,
    http://www.tvw.org (Weyerhaeuser's counsel noting that medical professionals
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    Street v. Weyerhaeuser Company, 93984-5
    become familiar with employment conditions in part through patients' explanations
    of their job duties). Instead, "[a] witness familiar with the worker's job requirements
    and the particular manner in which the worker performed those job requirements can
    provide evidence to assist the trier of fact to determine whether job conditions are
    distinctive." Br. of Amicus Curiae Wash. State Ass'n for Justice Found. at 13-14;
    see also 
    Bennett, 95 Wash. 2d at 533
    ("[L]ay witnesses may testify to such aspects of
    physical disability of an injured person as are observable by their senses and
    describable without medical training.").
    Given that the "arises naturally" requirement presents the nonscientific
    question of whether the conditions of a worker's particular employment are
    distinctive, it stands to reason that it can be established by lay testimony without the
    need for expert medical opinion.
    c. Washington Case Law Does Not Suggest the "Arises Naturally"
    Requirement Must Be Proved Through Expert Medical Testimony
    No Washington case holds that expert medical testimony is necessary to
    satisfy the "arises naturally" requirement. Weyerhaeuser argues, however, that
    language in several cases suggests a worker must prove a "distinctive employment
    cause" through expert medical testimony. Br. of Appellant at 15-18 (emphasis
    added).
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    Street v. Weyerhaeuser Company, 93984-5
    As an initial matter, Weyerhaeuser is mistaken to the extent it argues a worker
    must show a "distinctive risk" or "distinctive cause" to meet the "arises naturally"
    requirement. See, e.g., Pet. for Review at 5 ("Neither doctor addressed whether
    claimant's work activities presented a distinct risk of causing lumbar spondylosis."
    (emphasis added)); Br. of Appellant at 19 ("The issue whether particular work
    conditions constituted a 'distinctive' cause of a medical condition presents a medical
    question." (emphasis added)). As Street and supporting amicus point out, this "is no
    different than the argument that a worker must show that the particular employment
    exposed him or her to a greater risk of contracting the occupational disease than
    would other employments or everyday life." Br. of Amicus Curiae Wash. State
    Ass'n for Justice Found. at 15; see also Suppl. Br. of Resp't at 11-12. Because we
    previously rejected this "greater risk" requirement in Dennis, l 09 Wn.2d at 482,
    Weyerhaeuser is mistaken to the extent it advocates for adoption of this
    requirement. 1 A worker need only show "distinctive conditions" of employment to
    meet the "arises naturally" requirement.
    1
    As Street's counsel articulated at oral argument, requiring a worker to prove a
    distinctive cause or a distinctive risk of employment is inconsistent with the legislative
    history of the IIA, which now allows occupational disease claims for all employment, not
    just extrahazardous employment. Wash. Supreme Court oral 
    argument, supra, at 19
    min.,
    16 sec. through 20 min., 41 sec.; see also 
    Dennis, 109 Wash. 2d at 473-74
    .
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    Street v. Weyerhaeuser Company, 93984-5
    Weyerhaeuser's argument is also unpersuasive because the cases on which it
    relies do not support its position.     In Dennis, a sheet metal worker filed an
    occupational disease claim for osteoarthritis localized in his 
    wrists. 109 Wash. 2d at 468-69
    . This court reaffirmed that the "arises proximately" requirement "must be
    established by competent medical testimony which shows that the disease is
    probably, as opposed to possibly, caused by the employment." 
    Id. at 477
    . Because
    the worker's attending physician testified that "more probably than not, the
    osteoarthritis . . . was made symptomatic and disabling by . . . repetitive tin
    snipping," this court held that there was "sufficient medical evidence in the record
    from which a trier of fact could infer" the "arises proximately" requirement. 
    Id. Although the
    court discussed the "arises naturally" requirement, it neither stated that
    the requirement must be established by expert medical testimony nor focused on
    whether that requirement was satisfied. Instead, the court concluded merely that
    there was sufficient evidence to support the inference that the disabling wrist
    condition "arose naturally and proximately" out of employment. 
    Id. at 483.
    Dennis
    therefore does not support Weyerhaeuser' s argument. Had the court intended to
    require expert medical testimony for the "arises naturally" requirement, it could have
    stated so explicitly.
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    Street v. Weyerhaeuser Company, 93984-5
    In Potter v. Department ofLabor & Industries, 
    172 Wash. App. 301
    , 304, 306-
    07, 
    289 P.3d 727
    (2012), a lawyer filed an occupational disease claim after noticing
    strong odors in her newly remodeled office, experiencing bloody noses and fatigue,
    and being diagnosed with multiple chemical sensitivity disorder. The court found
    the lawyer failed to satisfy the "arises proximately" requirement because the medical
    testimony established only a possibility, not a probability, that she was exposed to
    chemicals in the remodeled office that made her sick. 
    Id. at 311.
    The court similarly
    found that the lawyer failed to satisfy the "arises naturally" requirement because, as
    the Board had found below, "'[r]emodels are everywhere, and by no means limited
    to law offices, or to work for that matter."' 
    Id. at 316.
    The court therefore upheld
    the denial of benefits. 
    Id. at 304.
    Nowhere in Potter did the court state it was
    upholding the denial of benefits because the lawyer failed to present medical
    testimony that remodels were a distinctive condition of her employment. To the
    contrary, the decision suggests that medical testimony is not necessary to make such
    a showing, as the Board made that determination on its own.
    In Gastv. Department ofLabor & Industries, 70 Wn. App. 239,241,852 P.2d
    319 (1993 ), a maintenance worker filed an occupational disease claim for a stress-
    related disease allegedly caused by being the subject of workplace rumors. On
    appeal, she challenged the trial court's jury instruction, which read:
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    Street v. Weyerhaeuser Company, 93984-5
    "If you find that Vickie Gast suffered a disease which was
    proximately caused by occurrences in her workplace, then you must consider
    whether or not such occurrences are distinctive conditions of her particular
    employment. This court has already ruled, as a matter oflaw, as follows:
    "(1) Rumors . . . by one's co-workers, are not, by themselves,
    distinctive conditions of employment."
    
    Id. at 242.
    The appeals court affirmed the denial of benefits and held that the trial
    court "correctly determined as a matter of law that rumors . . . are not distinctive
    conditions of employment."        
    Id. at 243.
        "Such conditions are unfortunate
    occurrences in everyday life or all employments in general. Their occurrence at a
    specific workplace is coincidental." 
    Id. As in
    Potter, 172 Wash. App. at 316
    , where
    the Board determined on its own that the lawyer's conditions of employment were
    not distinctive, the lower court in Gast found on its own that the maintenance
    worker's conditions of employment were not 
    distinctive, 70 Wash. App. at 243
    . This
    suggests that expert medical testimony is not necessary to satisfy the "arises
    naturally" requirement.
    As in Gast, 
    id. at 243-44,
    where the court held that rumors were not distinctive
    conditions of employment, the crux of the reasoning in Witherspoon v. Department
    of Labor & Industries, 
    72 Wash. App. 847
    , 851, 
    866 P.2d 78
    (1994), was that a
    coughing incident was merely coincidental with employment and could have
    happened anywhere. In Witherspoon, 
    id. at 848-49,
    a slaughterhouse worker filed
    an occupational disease claim for meningitis he allegedly contracted from a
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    Street v. Weyerhaeuser Company, 93984-5
    coworker who had coughed in his face in the locker room. In reversing the jury's
    award of benefits, the appeals court stated the "meningitis did not come about"
    naturally because "the medical testimony was that meningitis is spread" through the
    mouth and nose, and occurs almost everywhere. 
    Id. at 851.
    The worker's exposure
    to meningitis in the workplace "was merely coincidental and not a result of any
    distinctive conditions of his employment." 
    Id. Although the
    court relied on medical
    testimony to find the worker did not satisfy the "arises naturally" requirement,
    nowhere in the decision did the court say that such testimony is necessary. We do
    not read the decision as requiring expert medical testimony.
    Similarly, in Wheeler v. Catholic Archdiocese of Seattle, 
    65 Wash. App. 552
    ,
    567, 
    829 P.2d 196
    (1992), rev 'din part on other grounds, 
    124 Wash. 2d 634
    , 642-43,
    
    880 P.2d 29
    (1994), the court focused on the coincidental nature of the employment
    conditions.   There, a worker filed a negligent supervision claim against her
    employer, which argued the claim should have been dismissed under the IIA's
    exclusive remedy provision. 
    Id. at 565.
    On appeal, the court found the trial court
    did not err in refusing to dismiss the negligent supervision claim because it did not
    fall within the basic coverage of the IIA. 
    Id. at 566,
    568. The worker's claim was
    for a mental disability allegedly resulting from her supervisor's harassment. 
    Id. at 566.
      Without mentioning any medical testimony, the court found that "[t]he
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    Street v. Weyerhaeuser Company, 93984-5
    conditions ... were not particular to her occupation, but only coincidentally occurred
    in her workplace." 
    Id. at 567-68.
    Wheeler thus does not suggest that the "arises
    naturally" requirement must be established by medical testimony.
    As these cases illustrate, Washington case law does not support
    Weyerhaeuser's argument that a worker must prove the "arises naturally"
    requirement through expert medical testimony. See also Ruse v. Dep 't of Labor &
    Indus., 
    138 Wash. 2d 1
    , 7-8, 
    977 P.2d 570
    (1999) (affirming the denial of benefits
    without reaching the "arises naturally" requirement because the medical testimony
    did not support the "arises proximately" requirement); 
    Shreeve, 55 Wash. App. at 335
    -
    36 (upholding the award of benefits in part because the worker "presented the
    testimony of three doctors to support her contention that her kidney disease arose
    'proximately' out of her employment," but not stating whether such testimony
    supported the requirement that the disease arose "naturally" out of employment
    (emphasis added)); McClelland v. ITT Rayonier, Inc., 
    65 Wash. App. 386
    , 387, 393,
    
    828 P.2d 1138
    (1992) (rejecting the worker's occupational disease claim because he
    conceded that "his job was not unusually stressful" and the evidence therefore
    showed his depression was "caused simply by his own subjective but unrealistic
    view of the situation at" work rather than distinctive conditions of his employment).
    Rather, the remedial purpose of the IIA, the standard governing the admissibility of
    -22-
    Street v. Weyerhaeuser Company, 93984-5
    expert testimony, and the cases all indicate expert medical testimony is not required
    to prove a condition arises naturally out of employment.
    IL    The Evidence Was Sufficient To Support the Jury's Finding That
    Street's Chronic Low Back Condition "Arose Naturally and
    Proximately" Out of Distinctive Conditions of His Employment
    The remaining issue is whether sufficient evidence supported the jury's
    verdict that Street's low back condition is an occupational disease. At the superior
    court, the "party attacking the [Board's] decision" has the burden of proving it is not
    "prima facie correct." 
    Ruse, 138 Wash. 2d at 5
    ; RCW 51.52.115. At the appellate
    court, however, "'review is limited to examination of the record to see whether
    substantial evidence supports the findings made after the superior court's de novo
    review, and whether the [superior] court's conclusions of law flow from the
    findings."' 
    Ruse, 138 Wash. 2d at 5
    (quoting Young v. Dep't of Labor & Indus., 
    81 Wash. App. 123
    , 128, 
    913 P.2d 402
    (1996)).            Substantial evidence exists if it
    "convince[s] an unprejudiced, thinking mind of the truth of that to which the
    evidence is directed." Ehman v. Dep 't of Labor & Indus., 
    33 Wash. 2d 584
    , 597, 206
    P .2d 787 (1949).    The appellate court views the evidence "in the light most
    favorable" to the party who prevailed at the superior court. 
    Bennett, 95 Wash. 2d at 534
    .
    -23-
    Street v. Weyerhaeuser Company, 93984-5
    As noted, to succeed on an occupational disease claim, a worker must prove
    that the disease "arose naturally and proximately" out of employment. See 
    Dennis, 109 Wash. 2d at 481-82
    . The "arises proximately" requirement "must be established
    by competent medical testimony which shows that the disease is probably, as
    opposed to possibly, caused by the employment." 
    Id. at 477
    . "If, from the facts and
    circumstances and the medical testimony given, a reasonable person can infer that
    the causal connection exists, the evidence is sufficient." 
    Bennett, 95 Wash. 2d at 533
    .
    In reviewing the medical testimony on this issue, the "long-standing rule of law in
    workers' compensation cases [is] that special consideration should be given to the
    opinion of a [worker's] attending physician." Hamilton v. Dep 't ofLabor & Indus.,
    
    111 Wash. 2d 569
    , 571, 
    761 P.2d 618
    (1988). As established above, the "arises
    naturally" requirement need not be established by medical testimony. Rather, lay
    testimony may establish that the "occupational disease came about as a matter of
    course as a natural consequence or incident of distinctive conditions of''
    employment. 
    Dennis, 109 Wash. 2d at 481
    .
    Weyerhaeuser contends that Street's occupational disease claim fails because
    he "presented no expert testimony that addressed, directly or indirectly, the question
    whether his work activities were distinctive, compared to other employments and
    the activities of daily living." Br. of Appellant at 21. Weyerhaeuser emphasizes that
    -24-
    Street v. Weyerhaeuser Company, 93984-5
    neither Dr. Peterson nor Dr. Tsirulnikov compared Street's work activities to
    activities of daily living, and Dr. Rosenbaum testified that Street's work conditions
    were not distinctive. 
    Id. Street counters
    that Dr. Peterson's testimony was sufficient
    to prove that his low back condition "arose naturally and proximately" out of
    distinctive conditions of his employment because Dr. Peterson accurately described
    Street's work duties and opined that Street's employment more probably than not
    caused his low back condition. Suppl. Br. ofResp't at 7-9.
    While the evidentiary question presents a close call, we uphold the jury's
    verdict. Viewing the evidence in the light most favorable to Street and giving special
    consideration to Dr. Peterson's testimony, we hold there was sufficient evidence to
    support the jury's finding that Street's low back condition is an occupational disease.
    Dr. Peterson's testimony and Dr. Tsirulnikov's testimony were sufficient to
    establish that Street's low back condition "arose proximately" out of his
    employment. Dr. Peterson testified that Street's work more probably than not caused
    his low back condition, as opposed to everyday wear and tear. CP at 322-23, 326.
    Similarly, Dr. Tsirulnikov testified that Street's work more probably than not
    contributed to his low back condition, but he could not say to what extent. 
    Id. at 367-68,
    371.     Although Dr. Rosenbaum testified that Street's work did not
    proximately cause his low back condition, 
    id. at 411,
    the evidence must be viewed
    -25-
    Street v. Weyerhaeuser Company, 93984-5
    in the light most favorable to Street and need only reasonably suggest a causal
    connection. See 
    Bennett, 95 Wash. 2d at 533
    -34. Nor was the jury obligated to credit
    Dr. Rosenbaum's opinion. From the evidence, a rational trier of fact could infer the
    required causal connection between Street's employment and his low back
    condition.
    Street's testimony and his supervisor's testimony were sufficient to establish
    that Street's low back condition "arose naturally" out of distinctive conditions of his
    employment. Both Street and his supervisor testified that Street's duties included
    manhandling paper rolls that weighed on average 1,000 pounds. CP at 236-37, 261,
    288, 300-01. Street further testified that the paper machines he worked on are the
    world's biggest and fastest paper machines. 
    Id. at 230.
    "The weight of ... testimony
    is for the jury." 
    Bennett, 95 Wash. 2d at 534
    . A jury could conclude that manhandling
    paper rolls on the world's biggest and fastest machines was a distinctive condition
    of employment, as it does not occur in everyday life nor in all employments.
    Although we hold expert medical testimony is not required to establish Street's
    distinctive conditions of employment, Dr. Peterson's testimony is also helpful in
    resolving this issue. Dr. Peterson testified that Street used "a lot of his body weight"
    and his "abdominal muscles" in his employment, and she compared Street's job to
    her sedentary job. CP at 322-23. She testified that "people who use the body parts
    -26-
    Street v. Weyerhaeuser Company, 93984-5
    that are required in their job tend to wear those parts out." 
    Id. at 323.
    From this
    testimony, a jury could conclude that Street's job required more physical rigor than
    everyday life and work in general.
    Considering all the testimony, we hold that substantial evidence supported the
    jury's finding that Street's low back condition is an occupational disease.
    III.   Street Is Entitled to Attorney Fees on Appeal
    Street requests attorney fees on appeal. Both the superior court and the Court
    of Appeals awarded Street attorney fees pursuant to RCW 51.52.130. CP at 535;
    Street, slip op. at 13. That provision states,
    If, on appeal to the superior or appellate court from the decision and order of
    the board, said decision and order is reversed or modified and additional
    relief is granted to a worker ... or in cases where a party other than the
    worker ... is the appealing party and the worker's . . . right to relief is
    sustained, a reasonable fee for the services of the worker's ... attorney shall
    be fixed by the court.
    RCW 51.52.130(1).
    Because we affirm the lower courts' determination that Street's low back
    condition is an occupational disease, Street's right to relief is sustained on
    Weyerhaeuser's appeal and he is entitled to attorney fees.
    CONCLUSION
    We affirm the Court of Appeals. The remedial nature of the IIA, the standard
    governing the use of expert testimony, and our precedent all support the conclusion
    -27-
    Street v. Weyerhaeuser Company, 93984-5
    that a worker seeking industrial insurance benefits need not present expert medical
    testimony to satisfy the "arises naturally" requirement of an occupational disease
    claim. A worker need only present expert medical testimony to satisfy the "arises
    proximately" requirement. Given that Street's attending physician testified that his
    low back condition was more probably than not caused by his work, and given that
    Street and his supervisor testified as to Street's duties working in the paper mill,
    substantial evidence supported the jury's finding that Street's low back condition
    constitutes an occupational disease.
    -28-
    Street v. Weyerhaeuser Company, 93984-5
    WE CONCUR:
    -29-