A Relaxed Burden: Competent Medical Testimony Not Required to Prove a Key Element of Causation in Occupational Disease Claims

By Dallas Garner

In Street v. Weyerhaeuser Company, decided on August 10, 2017, the Washington Supreme Court continued its trend toward broad coverage of occupational disease claims. The decision was a disappointment, as the Court held that expert medical testimony is not required to prove that a worker’s occupational disease “arose naturally” from employment.[1]

To prevail on an occupational disease claim, a worker must prove that the disease “arose naturally and proximately” out of employment.[2] In the 1987 case of Dennis v. Department of Labor & Industries, the Court bifurcated the “arise naturally and proximately” phrase into separate lines of analysis.  For an occupational disease to “arise naturally” out of employment, it must come “about as a matter of course as a natural consequence or incident of distinctive conditions of . . . employment.”[3] To “arise proximately” out of employment, competent medical testimony must establish that the disease is probably, as opposed to possibly, caused by the employment.[4]

While Dennis established that expert medical testimony is necessary to satisfy the “arises proximately” requirement, Dennis left unsaid whether the same is true for the “arises naturally” requirement. The Street Court observed that its own decisions and the legislature’s amendments to the occupational disease statute “indicate a trend toward expanded coverage and a more relaxed burden of proof.”[5]

Also, since “arises naturally” requires an analysis of distinctive conditions of employment, as opposed to those employments in general or activities of daily living, Street found that the analysis presents a nonscientific question for which lay witness testimony is sufficient. In other words, the Court is unwilling to require doctors to familiarize themselves with various job duties.

Lastly, the Street Court found no Washington case law that suggested the “arises naturally” requirement must be proven through expert medical testimony. Based on the state’s legislative and judicial trend, the circumstances for which expert testimony is generally useful, and Washington case law, the Street decision held that lay witness testimony is enough to prove that an occupational disease came about as a result of distinctive employment conditions.

The Street decision represents at least the third time that the Washington Supreme Court has relaxed a worker’s burden of proof for an occupational disease claim. Even though the Court reduced a worker’s burden of proof, the benefit to employers is that a medical expert cannot testify in one fell swoop as to the “arises naturally” and “arises proximately” requirements. Instead, a worker must put an additional witness on the stand to satisfy the “arises naturally” requirement.

If you have any questions regarding the impact of the Street decision, do not hesitate to contact the attorneys at Wallace, Klor, Mann, Capener & Bishop, PC.



[1] Street v. Weyerhaeuser Company, —P.3d—(2017).

[2] See Dennis v. Department of Labor & Industries, 109 Wash.2d 467, 481-82, 745 P.2d 1295 (1987).

[3] Id. at 481.

[4] Id. at 477.

[5] Street v. Weyerhaeuser Company, —P.3d—(2017).