The Appeal CommissionThe Workers Compensation Act of Manitoba

Preamble

The worker is appealing the decision made by the Workers Compensation Board ("WCB") that their claim is not acceptable. A teleconference hearing was held on March 18, 2021 to consider the worker's appeal.

Issue

Whether or not the claim is acceptable.

Decision

The claim is not acceptable.

Background

The worker filed a Worker Hearing Loss Report with the WCB on May 5, 2014 indicating they suffered gradual hearing loss which they attributed to their employment from 1965 to 1995 with the employer. The worker noted that hearing protection was not provided by the employer, but hearing tests were performed.

On May 12, 2014, the WCB contacted the worker to discuss their claim. The worker confirmed the information on the Report and advised the only hearing test undertaken while they worked for the employer was done in 1965. Further, the worker advised they had noted their hearing slowly worsening since their retirement in 1995.

The employer provided its Employer Hearing Loss Report to the WCB on May 21, 2014. The employer noted a hearing protection program was implemented in 1970 with the worker being provided with hearing protection since that time and provided a copy of the worker’s audiogram results for tests done in 1984 and 1992.

An audiogram dated June 5, 2014 was provided to the WCB on June 11, 2014. The audiologist who conducted the test noted bilateral mild sloping to moderately severe high frequency sensorineural loss and recommended binaural hearing aids for the worker.

On July 23, 2014, the WCB obtained from the worker additional information regarding the various positions held while employed with the employer. Noise level testing results for the areas where the worker performed their job duties were not available. On July 24, 2014, the WCB advised the worker their claim for noise-induced hearing loss was not acceptable, as the audiogram evidence provided by the employer indicated the worker’s hearing was within normal levels until tested in 1992, at which time moderate changes in the worker’s left ear only were noted. In 1992, the worker was in a position that did not expose them to elevated noise levels. As such, the WCB could not establish the hearing loss was as a result of noise exposure at work.

On December 4, 2018, the worker requested reconsideration of the WCB’s decision to Review Office. In their submission, the worker noted the increase in their hearing loss from 1985 to 1992 as indicated in the audiogram results from the employer and that their hearing declined further after that time as they continued to be exposed to an ongoing noisy work environment while not wearing hearing protection. On December 17, 2018, the WCB received an additional audiogram dated November 21, 2018 that indicated moderately-severe sensorineural hearing loss and recommended binaural hearing aids for the worker’s hearing loss and bilateral tinnitus. The employer provided a response in support of the WCB’s decision on December 27, 2018. The worker provided a further detailed chronological submission on January 17, 2019.

On January 23, 2019, Review Office determined the worker’s claim was not acceptable as the onset of the worker’s hearing loss was asymmetrical, affecting their left ear only, and not bilateral as would be expected if due to exposure to noise at work. Therefore, the worker’s hearing loss was not due to exposure to noxious noise at work.

New medical information from an Ear, Nose and Throat (ENT) specialist was provided to the WCB on September 5, 2019. The August 29, 2019 report from the ENT specialist noted the specialist’s opinion regarding the worker’s asymmetrical loss that “…noise-induced hearing loss can be asymmetrical with one ear becoming more harmed by the noise and developing rapid deterioration.” This new medical information was provided to the Review Office on December 9, 2019 and the worker requested reconsideration of Review Office’s January 23, 2019 decision.

Review Office requested the WCB ENT specialist review the worker’s ENT specialist’s report and the worker’s file. In an opinion provided December 28, 2019, the specialist stated “Occupational NIHL (noise-induced hearing loss) is usually bilateral and symmetrical. I cannot find any occupational explanation on file or from the ENT specialist for this asymmetrical hearing loss.” Further, the WCB ENT specialist noted the audiogram from 2014 indicated worsening of the worker’s hearing some 19 years after their retirement from employment and queried whether the worker had been exposed to further noxious noise after their retirement. Review Office spoke with the worker’s representative on January 2, 2020 who advised the worker was not exposed to excessive noise following their retirement. On January 2, 2020, the employer again provided a submission in support of the WCB’s decision, with the worker providing a letter in support of their request from the treating ENT specialist on January 29, 2020.

On January 30, 2020, Review Office again found the worker’s claim was not acceptable. Review Office considered the additional medical information from the worker’s ENT specialist but preferred the opinion of the WCB’s ENT specialist that occupational noise-induced hearing loss is typically bilateral and symmetrical. Review Office did not accept the opinion of the worker’s ENT specialist that if the noise exposure in the workplace was excessive, it could lead to progression in hearing loss even after retirement, relying instead upon the WCB’s ENT specialist’s opinion that hearing loss does not progress after the exposure to noise is discontinued.

The worker’s representative filed an appeal with the Appeal Commission on May 27, 2020 and a teleconference hearing was arranged for March 18, 2021.

Following the hearing, the appeal panel requested additional medical information prior to discussing the case further. The requested information was later received and was forwarded to the interested parties for comment. On May 17, 2021, the appeal panel met further to discuss the case and render its final decision on the issue under appeal.

Reasons

Applicable Legislation and Policy

The Appeal Commission panels are bound by the provisions of The Workers Compensation Act (the "Act"), regulations under that Act, and the policies established by the WCB's Board of Directors.

Section 4(1) of the Act provides that where a worker suffers personal injury by accident arising out of and in the course of employment, compensation shall be paid. The Act defines “accident” in s 1(1) as follows: 

"accident" means a chance event occasioned by a physical or natural cause; and includes 

(a) a wilful and intentional act that is not the act of the worker, 

(b) any 

(i) event arising out of, and in the course of, employment, or 

(ii) thing that is done and the doing of which arises out of, and in the course of, employment, and 

(c) an occupational disease, 

and as a result of which a worker is injured.

The WCB's Board of Directors has established Policy 44.20.50.20, Noise-Induced Hearing Loss (the "Policy"), which provides, in part, that:

“Not all hearing loss is caused by exposure to noise at work. A claim for noise-induced hearing loss is accepted by the WCB when a worker was exposed to hazardous noise at work for a minimum of two years, based generally upon an average of 85 decibels for 8 hours of exposure on a daily basis. For every increase in noise level of 3 decibels, the required exposure time will be reduced by half.”

Worker’s Position

The worker appeared at the hearing represented by a worker advisor, who made a submission on behalf of the worker. The worker gave evidence through answers to questions posed by the worker advisor and by panel members.

The worker’s position, as outlined by the worker advisor, is that the hearing loss demonstrated by the audiological reports in the file is the result of exposure to noise in the workplace and therefore the claim should be accepted.

The worker advisor pointed to the file evidence that confirms the worker was employed in a noisy work environment for more than 31 years, beginning in 1964 and continuing until the worker’s retirement in 1995. The available evidence supports a finding that the noise exposure in the workplace exceeded the threshold requirement set out in the Hearing Loss Policy, of at least an average of 85 decibels for 8 hours daily over at least two years. While noise test results are not available for the period of the worker’s employment, the worker advisor urged the panel to rely upon the worker’s evidence as to the nature and kind of tools used in their work and the lack of hearing protection usage, as well as the information from the 2016 noise level assessment for the same workplace, provided by the worker to the WCB on January 17, 2019 as offering sufficient proof the worker was exposed to above-threshold noise levels in the course of their employment.

The worker advisor submitted that the panel should rely upon the January 29, 2020 opinion of the worker’s ENT specialist who stated that “...we know that occupation (sic) noise exposure is not always symmetrical and not always bilateral early on. This depends upon the sound source, as well as the handiness of the worker which side is exposed to the noise. It also has to do with which ear is more sensitive than the other.” In support of the position that the worker’s asymmetrical hearing loss, greater in the left ear in 1984 and 1992, was caused by noise exposure at work, the worker advisor directed the panel to consider the September 2018 medical literature submitted as evidence that the left ear of study participants was more susceptible to noxious noise than the right.

The worker advisor noted as well that the assertion by the WCB ENT advisor that the worker’s asymmetrical hearing loss related to use of a rifle in their youth is not supported by the evidence. The worker was exposed to noxious workplace noise for some 20 years by the time of the 1984 hearing test and had not used a rifle, by the worker’s report, since they were a youth.

The worker advisor relied upon the medical information presented by the WCB ENT advisor as confirming that occupational NIHL develops gradually over time due to continuous or intermittent noise exposure, noting the possibility of delayed effects in animal studies.

In sum, the worker’s position is that the available evidence supports the position that as a result of exposure to noisy work environments, the worker developed noise induced hearing loss and the claim should therefore be accepted.

Employer’s Position

The employer was represented in the hearing by its WCB officer, who made a submission on behalf of the employer.

The employer’s position is that that although the worker was exposed to noxious levels of noise in the course of their employment, the audiological evidence does not support that the worker experienced NIHL as a result. The employer’s representative noted that there is no occupational explanation for the worker’s asymmetrical hearing loss as indicated by the 1984 and 1992 audiograms. Further, the employer’s representative confirmed that the nature of the worker’s employment was such that there was not any exposure to noxious noise in the workplace after 1990.

The employer’s representative agreed with the determination of the Review Office on January 30, 2020 that there is no evidence that after the 1992 workplace hearing test, the worker was exposed to noxious noise levels in an amount sufficient to exceed the Hearing Loss Policy threshold and noting that based upon the hearing loss indicated by the worker’s 1992 test results, hearing aids would not have been required. The employer’s representative acknowledged that the worker was exposed to noxious noise levels in their work prior to commencing the foreman position in 1990 but noted that the evidence does not support that the worker developed occupational NIHL as a result of that exposure.

In sum, the employer’s position is that the worker’s claim is not acceptable as the evidence does not establish, on a balance of probabilities that the worker’s hearing loss was caused by their workplace noise exposure. Therefore, the appeal should not be granted.

Analysis

The issue on appeal is whether or not the claim is acceptable. For the panel to find that the claim is acceptable, it would have to determine that the worker’s hearing loss is the result of exposure to noise in the workplace. The panel was not able to make such a finding for the reasons that follow.

While the evidence supports that the worker now has bilateral sensorineural hearing loss and that there was a history of workplace noise exposure, not all hearing loss is caused by or the result of noise exposure in the workplace. Further, not all workers experience hearing loss as a result of such exposure.

The worker confirmed to the panel that they worked for the employer from 1964 to 1995 and outlined to the panel their job duties during those years, noting that their noise exposure was daily and not buffered by hearing protection. From 1990-95, when the worker was in a supervisory position, their use of noisy tools and noise exposure was irregular and most of their time was spent in an office environment. This evidence is supported by the information provided by the employer.

The audiogram tests in evidence from that period indicate results within the normal range in the worker’s right ear in 1984 and 1992, and noise induced hearing loss in the worker’s left ear in 1984 and 1992. The panel notes that for both ears there is little variation in the test results from 1984 to 1992, and with respect to the left ear at 6000Hz, there is no change at all from 1984 to 1992. If the worker’s hearing was compromised by exposure to workplace noise during this period, the panel would expect the 1984 and 1992 hearing test results to demonstrate this to be the case, but the similarity of the results from 1984 to 1992 suggests that the workplace noise exposure was not causing deterioration of the worker’s hearing.

The audiological evidence from June 11, 2014 indicates bilateral mild sloping to moderately severe high frequency sensorineural loss from 3000 – 8000 Hz. Further audiological test results from November 21, 2018 indicate “hearing sensitivities mainly within normal limits for an adult up to 1kHz sloping to a moderately-severe sensorineural loss” with significant shift in hearing sensitivities at 2000 and 3000 Hz. By the time of the 2014 audiological testing that indicated binaural sensorineural hearing loss, the worker was retired from their employment for nearly 20 years. With respect to post-retirement noise exposure, the evidence in the file is that the worker occasionally used power tools after retirement but always did so with hearing protection so as to limit their noise exposure.

The treating ENT specialist provided two opinions in support of the worker’s claim, on August 29, 2019 and January 29, 2020. In the August 29, 2019 opinion, the specialist stated that

“...in different handed individuals and in different exposures, noise-induced hearing loss can be asymmetrical with one ear becoming more harmed by the noise and developing rapid deterioration. The audiograms from 1984 and 1992 show that both ears were under duress in the high tones, and I would dispute the claims from the Review Office that only one ear is affected.”

The specialist goes on to note the worker’s minimal noise exposure over time from hunting and gun fire, none during the worker’s years of employment, whereas the worker had occupational exposure “as a noxious irritant” that outweighed the non-occupational exposures. The specialist also noted the worker is older and that “the auditory system will decline with age.” In the further opinion of January 29, 2020, the treating ENT specialist confirmed the earlier opinion provided and explained that “...if the stimulus in the workplace has been excessive, this can lead to added damage and progression even after the worker has retired.”

The WCB ENT advisor also provided two opinions for the panel to consider. The WCB ENT advisor’s December 28, 2019 opinion noted that

“The audiograms from [the employer], dated 1984 and 1992, show the hearing thresholds to be within the normal range in both ears, except for a 40 dB dip at 6000 Hz in the left ear. This dip is suggestive of early onset of NIHL in the left ear only. Occupational NIHL is usually bilateral and symmetrical. I cannot find any occupational explanation on file or from the ENT specialist for this asymmetrical hearing loss. The only explanation we have is the worker’s history of right-handed firearm use.”

In the April 14, 2021 opinion provided in response to the panel’s request for a further opinion taking into account the January 29, 2020 opinion of the treating ENT specialist, the WCB ENT advisor confirmed their earlier opinion and provided evidence to support that opinion. With respect to the typical symmetry of work-related NIHL, the WCB ENT advisor noted there may be exceptions caused by, for example, poorly fitted hearing protection or single sided exposure, or “situations in which the work involves fixed placement of the affected ear relative to the noise source.” The WCB ENT advisor again noted the absence of any such explanations in the evidence on the worker’s file. The WCB ENT advisor also elaborated on the effects of gun use on hearing, noting that such use “represents the classic basis for asymmetric hearing loss. In such cases, the ear closest to the gunshot blast and directly in line with the muzzle of the firearm is the one most affected. In the case of shooting from the right shoulder, the most affected ear would be the left ear.” With respect to the question of progression of hearing loss after the occupational noise exposure has ceased, the WCB ENT advisor pointed to medical literature stating that “Most scientific evidence indicates that hearing loss from noise does not progress (in excess of what would be expected from the addition of age-related threshold shifts) once the exposure is discontinued.”

The panel gave careful consideration to the opinions provided by both the treating ENT specialist and the WCB ENT advisor. Where those opinions differ, the panel accepts and relies upon the opinion provided by the WCB ENT advisor, noting that the treating ENT specialist has not provided any specific occupational explanation for the asymmetry in the worker’s hearing loss, nor provided any satisfactory occupational explanation as to the progression in the worker’s hearing loss in the 20 years after leaving that employment.

The panel finds that there is no occupational explanation on file that could account for the worker’s left ear hearing loss demonstrated as early as 1984 and again, in 1992, at the same level. Further the panel notes that the audiological evidence demonstrates a significant deterioration in the worker’s hearing after 1992 when the worker’s occupational exposure was already reduced, to 2014, some 19 years after the worker retired from that employment. The panel accepts that hearing loss from noise exposure does not typically progress once such exposure is discontinued and is unable to find any employment-related explanation for the deterioration of the worker’s hearing some 24 years after last working in a noisy work environment.

On the basis of the evidence reviewed and heard and on the standard of a balance of probabilities, the panel cannot establish that the worker’s bilateral sensorineural hearing loss was the result of workplace exposure to noise. Therefore, the panel concludes that the claim is not acceptable.

The worker’s appeal is dismissed.

Panel Members

K. Dyck, Presiding Officer
J. Witiuk, Commissioner
R. Ripley, Commissioner

Recording Secretary, J. Lee

K. Dyck - Presiding Officer
(on behalf of the panel)

Signed at Winnipeg this 27th day of May, 2021