Panel accepted noise exceeded OHS limits but audiogram pattern didn't match ONIHL criteria
Alberta's Appeals Commission for Workers' Compensation denies a noise-induced hearing loss claim on October 30, 2026, with hearing chair A. Edmunds writing for a unanimous panel.
The worker appealed a February 18, 2025 decision by the Workers' Compensation Board's Dispute Resolution and Decision Review Body (DRDRB) that denied his claim for occupational noise-induced hearing loss (ONIHL). The appeal turned on whether medical evidence supported the claim despite undisputed excessive noise exposure spanning nearly three decades.
The panel accepted the worker had been exposed to prolonged occupational noise exceeding limits set by Schedule 3 of Alberta's Occupational Health and Safety Code (Alta Reg 191-2021), based on the employer's Sound Level Survey, the worker's account, and the WCB audiologist's acknowledgement that his exposure had the potential to cause NIHL.
When the notch isn't there
Despite clearing the exposure threshold, the claim failed on medical causation. WCB Policy 03-01, Part II requires compensable NIHL be "the gradual loss of hearing due to prolonged occupational exposure to excessive noise levels" and "due, at least in part, to occupational noise exposure" in Alberta, with a clear history of prolonged exposure — typically two or more years.
The WCB audiologist reviewed the worker's September 12, 2022 audiogram and concluded the hearing loss pattern was not consistent with ONIHL. She explained the condition "typically produces a characteristic notch between 3,000 and 6,000 Hz, which was not present in either ear." She attributed the right ear loss to aging and the greater loss in the left ear to a conductive component.
The self-represented worker challenged these conclusions, arguing average noise readings failed to capture extreme events such as pressure release valve discharges reaching up to 160 dBA. He submitted online articles suggesting sudden loud noise can cause conductive hearing loss. The panel placed "greater weight on the WCB audiologist's opinion because it considers the worker's particular audiometric findings, whereas the information provided by the worker addresses the potential effects of sudden noise exposure generally."
Lost records, lost ground
A critical gap was the unavailability of historical workplace audiograms from the early 1990s. The worker recalled those tests showing greater hearing loss in his left ear, prompting advice to wear double hearing protection — earplugs and earmuffs. Despite efforts by both the worker and the WCB, those records were never located.
The panel accepted the worker's recollection but found that "without those results, we cannot determine whether his hearing loss at that time showed a pattern consistent with ONIHL." The absence of those records "does not establish or rule out whether he had ONIHL during his employment."
A July 25, 2024 audiometric report described bilateral sensorineural hearing loss and a minor asymmetrical gap at 1,000 to 3,000 Hz but offered no opinion on whether occupational noise contributed. The panel found this report did not advance the worker's case.
The causation bar holds firm
The applicable causation standard under WCB Policy 02-01 is the "but for" test: on a balance of probabilities, the injury would not have occurred but for the work exposures. The finding must be "based on the evidence and accepted medical knowledge, not on a speculative connection."
The panel recognized that "hearing loss associated with aging does not necessarily rule out a contribution from occupational noise exposure." However, it concluded the available medical evidence did not establish that occupational noise caused or contributed to the worker's hearing loss. The appeal was denied and the DRDRB's February 18, 2025 decision upheld.
The worker had confirmed at the outset he understood his right to representation, including free advocacy services, and chose to proceed without it.
