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 for hearing loss is not acceptable. A teleconference hearing was held on January 23, 2024 to consider the worker's appeal.

Issue

Whether or not the claim is acceptable.

Decision

The claim is not acceptable.

Background

On January 10, 2023, the worker submitted a Worker Hearing Loss Report with the WCB. Reporting a gradual hearing loss and tinnitus they related to their job duties with the employer. The worker noted the employer had provided hearing protection since 1977, which they wore until their retirement in 2003. The worker did not indicate any non-work related exposure to noise. On their Work History Summary, the worker noted they had started with the employer in June 1972, with hearing protection not available where they were exposed to loud noise for 8 hours a day until their transfer to another position with the employer in 1977. In that new position, the employer did provide hearing protection, the worker noted they were exposed to loud noise for 8 hours per day and they indicated their hearing was normal to gradual loss. In 1991 until their retirement in 2003, the worker held another position with the employer, again noting exposure to loud noise for 8 hours a day and indicated their hearing was normal to more severe hearing loss. Also included with the worker’s Report was a December 19, 2022 audiogram. The treating audiologist opined the worker had “…mild to profound sensorineural hearing loss…” in their right ear and “…moderate to severe sensorineural hearing loss…” in their left ear. In a discussion with the WCB on January 16, 2023, the worker confirmed the information in their Report and was advised of the WCB’s minimum threshold for acceptance of hearing loss claims of exposure to noise levels at or above 85 decibels for a minimum of 8 hours per day, for two years.

The employer provided their Employer Hearing Loss Report to the WCB on February 21, 2023. The employer noted the worker began their employment in 1972 and retired in 2002 but had not reported any hearing difficulty during that time. The employer noted their hearing protection program was implemented in 1970 and the worker had been regularly provided with hearing protection while at work. Also included with the Report were the worker’s hearing tests from April 29, 1987, April 24, 1989, May 18, 1990, July 19, 1994, August 15, 1996, April 12, 1999 and September 19, 2001.

The WCB advised the worker on March 20, 2023, their claim was not acceptable. The WCB noted the worker was employed with the employer from 1972 until their retirement in 2002, which was confirmed by the employer. The employer also confirmed hearing protection had been available since 1970. It was noted the September 19, 2001 audiogram, provided by the employer, indicated the worker did not require hearing aids and was not a typical configuration for noise-induced hearing loss. Further, as the worker had been removed from their exposure to occupational noise by retiring in 2002, any deterioration to their hearing would not be work-related. As well, it was noted the worker’s hearing loss was asymmetrical with noise-induced hearing loss typically being symmetrical.

The worker requested reconsideration of the WCB’s decision to Review Office on May 15, 2023. In their submission, the worker noted their treating audiologist supported the December 19, 2022 audiogram, which indicated the worker had noise-induced hearing loss which was consistent with excessive noise exposure from “…decades long work history in a heavy industrial noisy environment…”. The worker also listed several studies indicating the impact of noise-induced hearing loss in later years, contrary to the WCB’s decision that the effects of noise exposure stops after the exposure ends. A May 4, 2023 report from the worker’s treating audiologist was also included opining that noise-induced hearing loss occurs gradually, over a period of many years.

On August 1, 2023, Review Office determined the worker’s claim was not acceptable. Review Office found the worker had reported consistently wearing hearing protection throughout their employment, which reduced their exposure to noxious noise and once they retired, were no longer exposed to that noise. Review Office found the worker did not report any hearing difficulties to the employer and did not seek any medical treatment until December 2022. As such, the Review Office was unable to establish a relationship between the worker’s current hearing difficulties and their employment.

The worker filed an appeal with the Appeal Commission on September 14, 2023 and a hearing was arranged for January 23, 2024.

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 March 26, 2024, the appeal panel met further to discuss the case and render its final decision on the issue under appeal.

Reasons

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. The provisions of the Act in effect as of the date of the worker’s accident are applicable.

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", subject to subsection (1.1), includes 

(a) a chance event occasioned by a physical or natural cause, 

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

(c) an event or condition, or a combination of events or conditions, related to the worker's work or workplace, 

that results in personal injury to a worker, including an occupational disease, post-traumatic stress disorder or an acute reaction to a traumatic event;

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 in the hearing represented and supported by a family member. The worker’s family member made an oral submission on behalf of the worker, and the worker provided testimony in answer to questions posed by members of the appeal panel and by their representative.

The worker’s position is that the evidence confirms that they were exposed to noxious noise in the workplace and because of that exposure, developed noise induced hearing loss (“NIHL”). The worker noted that they used hearing protection that was made available to them in the form of ear plugs and earmuffs at times although it is unknown whether the hearing protection fully protected them from a noxious noise environment. The worker further noted a paper they submitted, which indicates that hearing protection technology has greatly improved over the past several decades.

With respect to the delay in filing a claim, the worker noted that as someone who is not a professional they simply accepted that NIHL was collateral damage that they had to live with given their former employment. The worker further indicated that they were not aware that they had NIHL until they were professionally diagnosed in December 2022.

Finally, the worker submitted that the 2001 audiogram should be considered unreliable given that there were uncertainties which could have impacted the test results. Accordingly, there was no definitive evidence that the hearing loss in 2001 was asymmetrical.

Employer’s Position

The employer’s position was that the claim was not acceptable given that the worker would have experienced NIHL prior to 2022 if the NIHL had been due to their occupation.

The employer noted that the worker wore hearing protection from 1977 to 2002 and the hearing loss appears to occur primarily after 2002 given the worker’s audiogram in 2001, nine months prior to the worker’s retirement, indicated that there was no evidence of significant hearing loss. The employer also noted that the Review Office’s decision was accurate in that the NIHL of the worker was not occupational given that the hearing loss was asymmetrical.

Analysis

The issue on appeal is whether the claim is acceptable. To find that the claim is acceptable, the panel would have to determine that the worker’s hearing loss is, on the balance of probabilities, the result of exposure to noise in the workplace. The panel was not able to make such a finding based on the evidence before us, as outlined in the reasons that follow.

The panel noted there is evidence that the worker currently has bilateral hearing loss and that there was a history of workplace noise exposure, but not all hearing loss is caused by or the result of noise exposure in the workplace. Further, not all workers experience hearing loss because of such noise exposure. For a claim to be accepted, there must be not only evidence of NIHL, but there must also be evidence of noise exposure in the workplace above the threshold established in the Policy. A claim for NIHL is accepted by the WCB when a worker was exposed to hazardous noise at work for a minimum of two years, based upon an average of 85 decibels for 8 hours of exposure daily.

In response to the appeal panel’s request for additional medical information, the WCB Healthcare Consultant indicated that the worker’s audiometric assessments of April 29, 1987, April 24, 1989, April 18, 1990, July 29, 1994 and August 15, 1996 revealed normal hearing thresholds across all frequencies in both ears. The WCB Healthcare Consultant further explained that this indicated that there is no evidence of hearing loss, including no evidence of noise induced hearing loss at either ear on any of the submitted audiograms from April 29, 1987 to August 15, 1996 inclusive.

March 29, 1999 audiogram

The WCB Healthcare Consultant then went on to analyze the March 29, 1999 audiogram, indicating that it showed that in the right ear there was a mild high frequency hearing loss (35 dB) at only 8000 Hz. They further explained that “decreased hearing at the sole level of 8000 Hz, representing the highest frequency measured on an audiogram, is indicative of age-related hearing loss (known medically as presbycusis).”

The WCB Healthcare Consultant further noted that the right ear had no audiometric notching of noise induced hearing loss and that “Notching on an audiogram is observed when there is a deficit in hearing at one of the higher frequencies of 3000, 4000 or 6000 Hz, with recovery at 6000 or 8000 Hz. The presence of an audiometric notch signifies the presence of at least a component of noise-induced hearing loss (NIHL).” Accordingly, the absence of an audiometric notch at the right ear on the March 29, 1999 audiogram is not in keeping with noise-induced hearing loss at the right ear at that time.

With respect to the left ear, the WCB Healthcare Consultant noted that the March 29, 1999 audiogram indicated a mild high frequency hearing loss at only 6000 Hz (30 dB) with an audiometric notch of 10 dBs from 6000 to 8000 Hz. The WCB Healthcare Consultant acknowledged that “the presence of an audiometric notch at the left ear on the March 29, 1999 audiogram indicates that there was a component of NIHL at the left ear at the time of testing.” However, the WCB Healthcare Consultant went on to note that the audiometric notch at the left ear on March 29, 1999 disappeared at the next audiogram of September 19, 2001. This indicates that the noise induced hearing loss at the left ear on March 29, 1999 was temporary, which is termed a temporary threshold shift.

September 19, 2001 Audiogram

The WCB Healthcare Consultant then analyzed the September 19, 2001 audiogram, indicating that it showed that in the right ear there was a mild high frequency hearing loss at 4000 Hz (30 dB) and at 8000 Hz (35 dB), with an audiometric notch of NIHL (15 dBs) from 4000 to 6000 Hz. They explained that the mild high frequency hearing loss (35 dB) at the right ear on the September 19, 2001 audiogram remained the same as was the case on the March 29, 1999 audiogram and that this remained in keeping with age-related hearing loss, i.e., presbycusis affecting the right ear. With respect to the new audiometric notch in the right ear, they explained that this indicates that in addition to presbycusis, there was a component of NIHL at the right ear on September 19, 2001.

With respect to the left ear, the WCB Healthcare Consultant noted that the audiogram indicated that the worker had normal hearing, with the lone exception of a mild (35 dB) high frequency hearing loss at 8000 Hz, which was consistent with age-related hearing loss. They also noted that the audiometric notch that had been present on the left side on the March 29, 1999 audiogram was not present on the audiogram of September 19, 2001, which indicates that it was temporary and that as of September 19, 2001, there was no noise-induced hearing loss at the left ear.

For further guidance, the WCB Healthcare Consultant noted that a medical evaluation for occupational NIHL includes consideration of the absolute results of pre-retirement audiograms, which was what they had considered with the workers various audiograms. With respect to principles which are followed for a medical evaluation for occupational NIHL the WCB Healthcare Consultant indicated that the worker’s temporary NIHL affecting the left ear only on March 29, 1999 and the worker’s unilateral NIHL affecting the right ear only on the 2001 audiogram are not in keeping with the principal characteristic of occupational NIHL that it is symmetrical in both ears. With respect to the worker’s argument that the 2001 audiogram was unreliable, the panel considered this argument and noted that in making its decision it must rely on the best evidence available at the time. Further, the panel noted that even if the 2001 audiogram is discounted as unreliable the evidence indicates that the 1999 audiogram reveals a component of NIHL in the left ear only making the NIHL asymmetrical and thus not consistent with occupational NIHL.

An additional guiding principle noted by the WCB Healthcare Consultant was that hearing loss due to continuous or intermittent noise exposure increases most rapidly during the first 10 to 15 years of exposure, following which the rate of hearing loss decelerates as the hearing threshold increases. Based on this principle the WCB Healthcare Consultant indicated that considering that the worker’s workplace noise exposure began in 1972 when they commenced employment, the majority of hearing loss attributable to workplace noxious noise exposure would likely have occurred by 1987 (15 years later), with lesser degrees of loss attributable to workplace noise exposure thereafter. Additionally, they noted that the first evidence of noise-induced hearing loss at the right ear was on September 19, 2001, 29 years after the worker’s workplace noise exposure began in 1972. They further noted that the exception to the above-noted principle would be if there had been a material increase in the intensity of occupational noise to which the worker’s right ear alone was exposed to between the March 29, 1999 and September 19, 2001 audiograms, in which case the interval onset of unilateral right sided noise induced hearing loss may be explained.

The panel notes that at the hearing, neither the employer nor the worker produced any evidence of a material increase in the intensity of occupational noise which the worker’s right ear alone was exposed to between the March 29, 1999 and September 19, 2001 audiograms. Further, the panel notes that there is no proximate audiogram after the audiogram September 19, 2001, which may have demonstrated that the worker’s audiometric notch in the right ear was temporary.

In considering the evidence, on the standard of a balance of probabilities, the panel is not able to establish that the worker’s hearing loss is the result of noise exposure at work. The medical evidence here indicates that there was a possibility that there was a NIHL component to the worker’s hearing loss in their right ear, however, such a finding would not be consistent with the principal that occupational NIHL is symmetrical, unless there is a reason for the asymmetry.

As such, while the panel accepts that the worker has hearing loss, we are unable to determine based on the evidence before us and on the standard of a balance of probabilities that this hearing loss is the result of their workplace exposure to noise. We therefore conclude that the claim is not acceptable, and the worker’s appeal is dismissed.

Panel Members

N. Smith, Presiding Officer
J. Peterson, Commissioner
M. Kernaghan, Commissioner

Recording Secretary, J. Lee

N. Smith - Presiding Officer
(on behalf of the panel)

Signed at Winnipeg this 19th day of April, 2024