Occupational Hearing Loss Policy 21-112 | Effective Date: September 26, 2018

Policy

Hearing loss is an occupational disease under section 13(u) of Regulation 84-66 of the WC Act when it is caused by industrial trauma or noise induced due to excessive levels of noise in the workplace. Eligibility for compensation is based on whether the personal injury by accident (hearing loss) arose out of and in the course of employment. 

When WorkSafeNB is satisfied the hearing loss was not caused by employment in New Brunswick, no compensation is paid. [ss 85(2) WC Act].

Hearing loss from aging is not work-related. It does not arise out of and in the course of employment as required by law, and therefore no benefits can be paid.

Interpretation 

  1. Applications for compensation must be made within one year of the date of accident. For occupational diseases, this is one year from the date of disablement. According to the ACOEM, disablement from noise-induced hearing loss occurs during the period of exposure (increasing most rapidly in the first 10 to 15 years of exposure and then decelerates).
  2. Therefore, the date of disablement (accident) is the earlier of:
  • Date of an audiogram which shows evidence of noise-induced hearing loss; or
  • Last exposure to noise in the workplace at a level and duration significant enough to have caused the hearing loss.
  1. The WC Act provides authority to WorkSafeNB to extend application when it considers the delay is justified.

Persuasive Evidence of Occupational NIHL

  1. Noise exposure averaging over 85 dB(A) for eight hours per day, for a minimum of two years, or the equivalent. 
  2. Hearing loss greater than 25 dB for at least one test frequency within the 3000 Hz to 6000 Hz frequency range. 
  3. A pattern of hearing loss consistent with the medical characteristics of noise-induced hearing loss as outlined in the ACOEM Guidance Statement, including:

a) It is sensorineural;

b) Hearing loss is usually in both ears, unless there is evidence of unilateral exposure;

c) Its first sign is a notching of the audiogram at high frequencies of 3000, 4000, or 6000 Hz with recovery at 8000. The hearing test must be performed at all frequencies from 250 to 8000 hertz.

d) It almost never produces a loss greater than 75 decibels in high frequencies, and 40 decibels in lower frequencies.

  1. The Attributable Risk Fraction is greater than 50% and all other evidence weighs more heavily toward the hearing loss being caused by the employment. 
  2. Exposure to hazardous noise levels must have occurred at work for a claim to be accepted. In addition to the above, WorkSafeNB weighs all available evidence including: the use of hearing protection, evidence of noise conservation programs in the workplace, and audiograms conducted by employers and healthcare providers.

Medical Aid 

  1. For accepted NIHL claims, medical aid may be in the form of a hearing aid.
  2. Workers are responsible for the day-to day care and maintenance of the hearing aid.  
  3. WorkSafeNB determines the need to replace a hearing aid based on evidence, however WorkSafeNB will not replace hearing aids more than once every five years, unless medically necessary as determined by WorkSafeNB.

Permanent Physical Impairment          

  1. WorkSafeNB evaluates injured workers for a permanent physical impairment (PPI) award resulting from hearing loss under Regulation 82-165 Permanent Physical Impairment Rating Schedule. 
  2. Reassessment for permanent physical impairment will only be considered where there has been continued exposure to hazardous noise levels at the place of employment.

 

“The Merck Manual – 2nd Home Edition”, Merck Research Laboratories, 2003.

ISO 1999-1990. Acoustics - Determination of occupational noise exposure and estimation of noise-induced impairment. Internat. Standard ISO 1999. 2nd ed. Geneva, 1990.

American College Of Occupational And Environmental Medicine (ACOEM). “ACOEM Guidance Statement: Occupational noise-induced hearing loss.” JOEM 54, 1 (January 2012): 106-108.

 

ACOEM – the American College of Occupational and Environmental Medicine represents more than 4,500 physicians and other health care professionals specializing in the field of occupational and environmental medicine; dedicated to promoting the health of workers through preventive medicine, clinical care, research, and education.

Attributable Risk Fraction - is a figure derived from the overall strength of association and is a measure of the proportion of cases of the disease that are reasonably attributable to the exposure.

Decibel “dB” – a unit for expressing the relative intensity of sounds on a scale from zero for the average least perceptible sound to about 130 for the average pain level (Webster’s Collegiate Dictionary).

Decibel(A) “dB(A)” – levels of dBs weighted according to the weighting curves to approximate the way the human ear hears. 

Noise-induced hearing loss (NIHL) - a permanent decrement in hearing threshold levels (HTLs), with a characteristic reduction of hearing sensitivity at the frequencies of 3, 4, and/or 6 kHz, and relatively better hearing sensitivity in surrounding frequencies, i.e., 2 or 8 kHz (WHO).

Sensorineural hearing loss – hearing loss due to damage to the sensory structures (hair cells) of the inner ear, auditory nerve, or auditory nerve pathways in the brain (Merck Manual).

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