Decades can pass between a worker's exposure to hazardous noise and the final calculation of compensation for hearing loss. In Decision No. 73/08, 2008 ONWSIAT 630, the Ontario Workplace Safety and Insurance Appeals Tribunal considered how to calculate a pension for an operator whose right and left ears showed different levels of hearing damage.
The worker operated heavy equipment between 1956 and 1989. A 2004 audiogram showed asymmetrical hearing loss. The Board accepted occupational hearing loss and made an award based on the loss in the left ear and a matching level in the right ear, but excluded the additional loss in the right ear. The worker appealed.
The Tribunal reasoned that hearing loss developing after exposure ends isn't attributable to that exposure. The compensable loss therefore had to be assessed by reference to 1989, when the worker stopped the noisy work, rather than simply treating the 2004 audiogram as the accident date. That brought the compensation regime in effect before 1989 into play. There was limited medical evidence available to separate different causes of the asymmetry, so the Vice Chair accepted the Board's approach to the compensable component of hearing loss.
Applying the Board's adjustment for age related hearing loss, the Tribunal calculated a 4.2% hearing loss pension and added 2% for tinnitus. The resulting 6.2% pension was retroactive to 1989. The appeal was allowed in part.
The case illustrates how causation, the period of occupational exposure, later testing and the applicable statutory regime can each affect an occupational disease claim. The particular pension percentages and adjustment method belong to the historical regime applied in this decision and shouldn't be imported into current claims without verification.
Source note: This commentary draws on WSIAT's official published counsel summary of Decision No. 73/08, rather than the unavailable historical PDF.