                                                        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 Wn.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


                                           -2-
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


                                           -3-
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


                                           -4-
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


                                           -5-
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


                                          -6-
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 Wn.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 Wn.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




                                           -7-
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



                                            -8-
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 Wn.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.




                                          -9-
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




                                           -10-
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 Wn.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


                                          -11-
Street v. Weyerhaeuser Company, 93984-5




the burden of proof requirement." Dennis, 109 Wn.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 Wn. 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 Wn. App.

283, 286-87, 792 P.2d 1269 (1990) (quoting Kinville, 35 Wn. 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 Wn.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.




                                          -12-
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 Wn.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 Wn.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




                                              -13-
Street v. Weyerhaeuser Company, 93984-5




779 (rev. 1979); Bennett v. Dep 't of Labor & Indus., 95 Wn.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


                                          -14-
Street v. Weyerhaeuser Company, 93984-5




observable job activities. See, e.g., City ofBremerton v. Shreeve, 55 Wn. 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 Wn.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


                                          -15-
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 Wn.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).




                                           -16-
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 Wn.2d at 473-74.

                                           -17-
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 Wn.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.




                                          -18-
Street v. Weyerhaeuser Company, 93984-5




      In Potter v. Department ofLabor & Industries, 172 Wn. 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:


                                          -19-
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 Wn. 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 Wn. 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 Wn. 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


                                          -20-
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 Wn. App. 552,

567, 829 P.2d 196 (1992), rev 'din part on other grounds, 124 Wn.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


                                          -21-
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 Wn.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 Wn. 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 Wn. 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 Wn.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 Wn.2d at 5 (quoting Young v. Dep't of Labor & Indus., 81

Wn. 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 Wn.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 Wn.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 Wn.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 Wn.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 Wn.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 Wn.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 Wn.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 Wn.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-
