Notwithstanding any other law to the contrary, any condition of impairment of health caused by any disease of the heart, lungs, or respiratory system resulting in permanent incapacity to a sewer worker shall be presumed to have been suffered in the actual performance of duty at some definite time and place through no wilful negligence on the sewer worker's part, and as a result of the inherent occupational hazard of exposure to the inhalation of smoke, toxic gases, chemical fumes, and other toxic vapors, unless the contrary be shown by competent evidence; provided that the sewer worker shall have passed a physical examination on entry into such service or subsequent to such entry, which examination failed to reveal any evidence of such condition.
HRS § 88-336