This opinion was filed for record at 

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.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. Filed 

### AUG 1 0 

## 2017 ----'-----=..:::__:_:_- STEPHENS, J.-WeyerhaeuserCompany, RogerA. Street's former employer, challenges Street's award ofindustrial insurance benefits for his lowback 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 courtheldthataworker seekingbenefitsfor anoccupationaldiseasemustpresentexpert medical testimony that the disease "arise[s] 'proximately"' out of employment. Weyerhaeuser argues that in light ofDennis, such a worker must also present expert medical testimonythatthe disease "arisesnaturally" out ofemployment.Street v. Weyerhaeuser Company, 93984-5



### The Court ofAppeals rejected Weyerhaeuser's argument, holding that neither Dennis 

### nor any other appellate decision requires Street to present expert medical testimonyto showthathisbackcondition "arosenaturally" 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 Streetproved his low back condition is an occupational disease and affirmed thejury award ofbenefits. We affirm the Court ofAppeals. BACKGROUND FACTS AND PROCEDURAL HISTORY Street worked for Weyerhaeuser or its subsidiary (Norpac) his entire career. In 1991, Street began working in one ofNorpac's paper mills, where he held various positions for the next20 years. Although Streethadbackproblems priorto working in the papermill, he did not find the problems disabling until he was injured atthe mill in 2011. More than one year later, Street applied for workers' compensationbenefits 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 ofthe date on which the injury occurred), with 

### RCW 51.28.055(1) (worker must file occupational disease

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claim within two years ofthe date the workerhad notice ofthe occupational disease or ofthe ability to file a claim for disability benefits). Street appealed the Department's order and letterto the Board ofIndustrial InsuranceAppeals (Board), clarifyingthathe 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 summaryjudgment, 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, andthree 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 ofthe paper machine so that the machine could produce individual paper rolls. His duties also included monitoringpapermachines, repairingbrokenmachines, "manhandling"paper rolls by grabbing and pushing the core ofthe roll, bending over to sand cores, and tackingbarcodes onto the finished paperrolls. The paperrolls were approximately40 to 50 inches in diameter and weighed on average 1,000 pounds. The cores, on which therolls wereplaced, weighedonaverage2 to 10pounds. Streetworked 12-hourshifts with few breaks, ifany. Some of Street's work became automated over the last 10

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years, andduringthelastcoupleofyears, Streetworkedinaless demandingmonitoring role about 30percent ofthe time. RichardT. Moore, Street's supervisorof twoto five years, gave slightlydifferent testimony regarding Street's role. Moore testified that Street held the less demanding monitoring role about 75 percent ofthe time, that Street sat approximately 20 percent of the time as an assistant winder operator, and that workers typically had help manhandling the paperrolls, which mighthappen Oto 12 times a day. Dr. Patricia Peterson, Street's primary care physician of20 years, testified that she was familiar withthe nature ofStreet's work "[t]o some degree" and described his role inthe papermill as a "veryheavyjob,
... a movingjob,
... [not]justa sit around andwatchthings gojob." Clerk's Papers (CP) at 313,315,319,321. Shetestifiedthat 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. Althoughon Street's short-term disabilityclaimform shehad checked aboxindicating that the condition was not workrelated, she latertestified on a more probable than not basis that the kind ofwork Street did, as opposed to everyday wear and tear ofdaily living, at least in part caused Street's lowback condition because he used "alot ofhis bodyweight" and his "abdominal muscles" inmanhandling paperrolls. 

### Id at 322-23, 326. Dr. Peterson acknowledgedthat eventhough Street had come in with complaints

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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,thoughhe couldnot sayto "whatextent" itcontributed. 

### Id. at 362,364, 367- 68, 371. Heindicatedthat Street'sweight, genetics, and "probably some otherphysical 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," ifat all. 

### Id. at431-32. 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 ofbenefits, butdirectedtheDepartmentto find that Street filed an
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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 forjudgment as a matter oflaw onthe ground that Street failed to present expertmedicaltestimonythathis lowbackcondition "arosenaturally" outof distinctive conditions ofhis employment. The superior court denied the motion and sent the case to trial. Thejury found that Street's back condition is an occupational disease that arose "naturally and proximately" out ofthe distinctive conditions ofhis employment. 

### Id. at 532. Based onthe verdict, the superior courtreversed 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 ofthe Court ofAppeals. Order Transferring Cases, Street v. Weyerhaeuser Co., No. 48559-1-II (Wash. Ct. App. Aug. 16, 2016). In
an unpublished decision, the Court ofAppeals affirmed, holding that Street was not required to presentmedical testimonyto satisfythe "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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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. Streetv. Weyerhaeuser Co., 187 Wn.2d 1025, 391 P.3d 457 (2017). ANALYSIS The Industrial Insurance Act (IIA), Title 51 RCW, provides "sure and certain relieffor workers, injured in their work." RCW 51.04.010. Workers "who suffer[] disability from an occupational disease in the course ofemployment" are entitled to "the same compensationbenefits" as injured workers. RCW 51.32.180. Inthepresent case, Street alleges that his chronic lowbackcondition is an occupational disease. CP at 57. "'Occupational disease' means such disease
... as anses naturally and proximately out ofemployment." 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 "'mustbe the proximate cause ofthe 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.2d472,479,202P.2d448 (1949)). This "causalconnection
...mustbeestablished

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by competent medical testimony which shows thatthe disease is probably, as opposed topossibly, caused bythe employment." Id. "Arises naturally" requires a workerto establish that his or her occupational disease came about as a matter ofcourse as a natural consequence or incident of distinctive conditions of his or her patiicular employment. The conditions need notbe 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 itselfis 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 ofthat worker's particular employment. Finally, the conditions causing the disease
... must be conditions ofemployment, that is, conditions of the worker's particular occupation as opposed to conditions coincidentally occurring inhis orherworkplace. 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 specificallyaddress whetherexpertmedicaltestimonyisrequiredtoprove it. Thatissue is nowbefore 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 ofemployment constitutes an

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issue ofmedical causation that must be proved through expert medical testimony. Pet. forReviewat 8, 19. Streetcountersthatwhilethe "arisesnaturally"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 notrequire expert opinion. Id. at 5; Br. ofResp't at 12-13. We believe the remedial nature ofthe IIA, the standard governing the need for expert testimony, and our case law all support Street's argument. We discuss each ofthese reasons more fully below.
a. The IIA Is Broadly Construed in Favor ofWorkers 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 ofthe worker." Dennis, 109 Wn.2d at 470. "With this principle inmind," id., boththe 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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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 withinthe definition ofan "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," althoughcompensationwas availableonlyfor extrahazardous employment. Id. Finally, the legislature eliminatedthe 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 ofoccupational disease, the Legislature has repeatedly and consistently provided expanded coverage for disability resulting from occupational disease." Id. at473-74. This courtconcludedthatitwas anatural next step to expand

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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 ofprooffor an occupational disease claim. First, in Sacred Heart Medical Center v. Carrado, 92 Wn.2d 631, 632-33, 600 P.2d 1015 (1979), this courtheldthatthe medicaltestimonywas sufficientto supportthejury's finding that a nurse had contracted hepatitis as a result ofher 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 ifthe medical testimony shows the causal connection." Id. In other words, it is sufficient if"areasonable 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 ofmedical causation. Indeed, in later describingits holding, this court stated, "SacredHeartdoes notrequire each [worker claiming] occupational disease coverageto prove an increasedrisk ofdisease-based disability due to conditions ofhis or her particular employment, but instead eases

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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, 

### "whichrequired the worker to prove 'thatthe conditionsproducinghis disease arepeculiar to, orinherent in, 

### his particular occupation."' KaiserAlum. & Chem. Corp. v. McDowell, 

### 58 Wn. App. 283, 286-87, 792 P.2d 1269 (1990) (quotingKinville, 

### 35 Wn. App. at 87). InDennis, 

### 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 ofproof. Allowing a worker to prove the "arises naturally" requirement without the necessity ofmedical testimony aligns with this trend.

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b. Expert Medical Testimony Is Necessary Only for Issues ofMedical 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]fscientific, technical, or other specialized knowledge will assist the trier offact to understand the evidence
orto determine a fact in issue," a qualified expert "maytestifythereto in the form of
an opinion." ER 702. With regard to expert medical testimony, the "general rule" is thatexpert medical testimony is required on only those matters "strictly involvingmedical science". Thebasic question is whethertheparticular 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 "thenature oftheharm which mayresult andtheprobability ofits occurrence" because "[o]nly a physician
... is capable of judging what risks exist and their likelihood ofoccurrence" (alteration in original) (citation omitted) (quoting 2 JOHNHENRY WIGMORE, EVIDENCE IN TRIALS AT COMMON LAW§ 568, at

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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"' ofthe disability. Eyer v. Dep'tof Labor & Indus., l Wn.2d 553, 555, 96 P.2d 1115 (1939) (quotingAtl. RefCo. v. Allen, 1939 OK 116, 185 Okla. 194, 195, 90 P.2d 659); see also Hoff v. Dep'tof Labor &Indus., 198 Wash. 257,266, 88 P.2d 419 (1939) ("[U]pon a medical question regarding the nature and effect ofa 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. ofAppellant at 19. We find this argument unavailing. "Arises proximately" means that the employmentconditions mustbetheproximate cause of the disease. Dennis, l09 Wn.2d at477. "Arisesnaturally" means thatthe conditions of a worker's particular employment are distinctive, i.e., different from, employments in general oractivities ofdailyliving. Id. at481. The first requirement involves an issue of medical causation, but the second requirement pertains to

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observablejob activities. See, e.g., City of Bremerton 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."). Viewingtherequirementsthis wayexplains whythe court inDennis explicitly stated only that expert medical testimony is necessary for the "arises proximately" requirement. See 109 Wn.2d at477. Medicalprofessionals specialize in diagnosing patients' conditions, not in familiarizing themselves with variousjob duties. Street aptly notes that many treating physicians would balk at any requirement that they "become experts as tojob duties that exist in all employments in general, or testify
as to what constitutes activities ofdaily living, versus distinctivejobduties." Suppl. Br. ofResp'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 particularemployment are distinctive." Br. ofAmicus Curiae Wash. State Ass'nfor 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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become familiar with employment conditions in partthrough patients' explanations oftheirjobduties). Instead, "[a] witness familiarwiththe worker'sjobrequirements andtheparticularmannerin whichtheworkerperformedthosejobrequirements can provide evidence to assist the trier offact to determine whetherjob conditions are distinctive." Br. ofAmicus 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 canbe established bylay testimony without the need for expertmedical opinion.
c. Washington Case Law Does Not Suggest the "Arises Naturally" Requirement Must Be Proved Through ExpertMedical 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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As an initial matter, Weyerhaeuser is mistakentothe 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 ofcausing lumbar spondylosis." (emphasis added)); Br. of Appellant at 19 ("The issue whether particular work conditions constituted a 'distinctive' cause ofamedical conditionpresents amedical question." (emphasis added)). As Streetand supporting amicus pointout, this "isno different thanthe argument that a workermust showthat the particular employment exposed him or her to a greater risk of contracting the occupational disease than would other employments or everyday life." Br. ofAmicus Curiae Wash. State Ass'n for Justice Found. at 15; see also Suppl. Br. ofResp't at 11-12. Because we previously rejected this "greater risk" requirement in Dennis, l09 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" ofemployment 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 ofthe 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 offact could infer" the "arises proximately" requirement. Id. 

### Although the court discussedthe "arises naturally" requirement, itneither statedthat 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 ofemployment. Id. 

### at 483. Dennis 

### therefore does not support Weyerhaeuser's argument. Had the court intended to require expertmedicaltestimonyfor the "arisesnaturally"requirement, it couldhave stated so explicitly.

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InPotter v. Department of Labor &Industries, 172 Wn. App. 301, 304, 306- 07, 289 P.3d 727 (2012), a lawyer filed an occupational disease claim afternoticing strong odors in her newly remodeled office, experiencing bloody noses and fatigue, and being diagnosed with multiple chemical sensitivity disorder. The court found the lawyerfailed to satisfythe "arisesproximately"requirementbecausethe medical testimony established only a possibility, not a probability, that she was exposed to chemicals intheremodeled officethatmade 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 ofbenefits. 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 ofher employment. To the contrary, the decision suggests thatmedical testimony is not necessaryto make such
a showing, as the Board made that determination on its own. In Gastv. Departmentof Labor &Industries, 70 Wn. App. 239,241,852P.2d 319 (1993), a maintenance worker filed an occupational disease claim for a stressrelated disease allegedly caused by being the subject of workplace rumors. On appeal, she challenged the trial court'sjuryinstruction, which read:

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"If you find that Vickie Gast suffered a disease which was proximatelycaused by occurrences in herworkplace, then you must consider whether or not such occurrences are distinctive conditions ofher particular employment. This courthas already ruled, as a matter oflaw, as follows: "(1) Rumors
... by one's co-workers, are not, by themselves, distinctive conditions ofemployment." Id. at 242. The appeals court affirmed the denial ofbenefits and held that the trial court "correctly determined as a matter oflaw 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 ofemployment were not distinctive, the lower court in Gast found on its own that the maintenance worker's conditions ofemployment 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. at243-44, where the courtheldthatrumors werenot distinctive conditions ofemployment, the crux ofthe reasoning in Witherspoon v. Department ofLabor & 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
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coworker who had coughed in his face in the locker room. In reversing thejury's award ofbenefits, the appeals court stated the "meningitis did not come about" naturallybecause "themedicaltestimony 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 ofhis employment." Id. Althoughthe courtrelied 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 'dinparton othergrounds, 124 Wn.2d 634, 642-43, 880 P.2d 29 (1994), the court focused on the coincidental nature ofthe 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 ofthe 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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conditions
...were notparticularto her occupation,but onlycoincidentally 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 ofbenefits without reaching the "arises naturally" requirement because the medical testimony didnot supportthe "arisesproximately" requirement); Shreeve, 55 Wn. App. at 335- 36 (upholding the award of benefits in part because the worker "presented the testimony ofthree 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. ITTRayonier, Inc., 65 Wn. App. 386, 387, 393, 828 P.2d 1138 (1992) (rejecting the worker's occupational disease claimbecausehe 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 ofthe situation at" workrather than distinctive conditions ofhis employment). Rather, the remedial purpose ofthe IIA, the standard governing the admissibility of

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experttestimony, andthe cases all indicate expert medical testimony is notrequired to prove a condition arises naturally out ofemployment. 

### IL The Evidence Was Sufficient To Support the Jury's Finding That Street's Chronic Low Back Condition "Arose Naturally and Proximately" Out ofDistinctive Conditions ofHis 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 ofproving 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 ofthe 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.

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As noted, to succeed on an occupational disease claim, a worker must prove that the disease "arose naturally and proximately" out ofemployment. 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 bythe 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 oflaw in workers' compensation cases [is] that special consideration should be given to the opinion ofa [worker's] attending physician." Hamilton v. Dep 't of Labor &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 experttestimonythat addressed, directly or indirectly, the question whether his work activities were distinctive, compared to other employments and the activities ofdaily living." Br. ofAppellant at 21. Weyerhaeuseremphasizesthat

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neither Dr. Peterson nor Dr. Tsirulnikov compared Street's work activities to activities ofdaily living, and Dr. Rosenbaum testified that Street's work conditions
werenot distinctive. Id. StreetcountersthatDr. Peterson'stestimonywas sufficient to prove that his low back condition "arose naturally and proximately" out of distinctive conditions ofhis employment because Dr. Peterson accurately described Street's work duties and opined that Street's employment more probably than not caused his lowback condition. Suppl. Br. ofResp't at 7-9. While the evidentiary question presents a close call, we uphold the jury's verdict. Viewingthe evidence inthe lightmostfavorable to Street and giving special consideration to Dr. Peterson's testimony, we hold there was sufficient evidence to supportthejury'sfinding that Street's lowbackconditionis 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. Petersontestifiedthat Street'sworkmoreprobablythannotcaused 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

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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 thejury obligated to credit Dr. Rosenbaum's opinion. Fromthe evidence, a rational trier offact could inferthe 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 lowback condition "arosenaturally" out ofdistinctive conditions ofhis employment. Both Street and his supervisor testified that Street's duties included manhandling paperrolls 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'sbiggestand fastestpapermachines. Id. at 230. "Theweight of
...testimony is for thejury." Bennett, 95 Wn.2d at 534. Ajurycould conclude thatmanhandling 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 resolvingthis issue. Dr. Petersontestifiedthat Streetused "alot ofhis body weight" and his "abdominal muscles" in his employment, and she compared Street'sjob to her sedentaryjob. CP at 322-23. She testified that "people who use the body parts

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that are required in theirjob tend to wear those parts out." Id. at 323. From this testimony, ajurycould conclude that Street'sjob required more physical rigor than everyday life and work in general. Considering all thetestimony, we holdthat substantial evidence supportedthe jury'sfinding that Street's lowback condition is an occupational disease. III. Street Is Entitled to Attorney Fees on Appeal Streetrequests attorney fees on appeal. Boththe superior court and the Court ofAppeals awarded Street attorney fees pursuant to RCW 51.52.130. CP at 535; 

### Street, slip op. at 13. Thatprovision 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 ofthe worker's
... attorney shall be fixed bythe 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 ofAppeals. The remedial nature ofthe IIA, the standard governing the use ofexperttestimony, and ourprecedent all support the conclusion
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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.

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WE CONCUR:

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