Wash. Rev. Code § 51.08.140 : — INDUSTRIAL INSURANCEDEFINITIONS — "Occupational disease." TEXT PDF "Occupational disease" means such disease or infection as arises naturally and proximately out of employment under the mandatory or elective adoption provisions of this title. RCW 51.08.140 1961 c 23 § 51.08.140. Prior: 1959 c 308 § 4; 1957 c 70 § 16; prior: 1951 c 236 § 1; 1941 c 235 § 1, part; 1939 c 135 § 1, part; 1937 c 212 § 1, part; Rem. Supp. 1941 § 7679-1, part.