REDUCING CLAIMS: Allocation of Responsibility for Occupational Noise-Induced Hearing Loss (ONIHL)

Transcription

1 REDUCING CLAIMS: Allocation of Responsibility for Occupational Noise-Induced Hearing Loss (ONIHL) Occupational Noise-Induced Hearing Loss remains one of the most prevalent occupational diseases in spite of the establishment of hearing conservation programs in many industries. In many jurisdictions, allocation of responsibility can be shared among several employers. Also, several causes, such as non-occupational exposure to noise, medical conditions and the presbycusis factor can be considered. A scientific approach has been developed to allocate responsibility of ONHIL to previous employers based on a sequential order of exposure. As stated by the American Academy of Otolaryngology: NIHL is a decelerating process; the largest changes occur in the early years, with progressively smaller changes in the later years. 1 Using ANSI S3.44 prediction formulas 2, a scientific statistical approach has been developed for otologically normal subjects to allocate responsibility of acquisition of ONHIL according to the sequential order of exposure. While the application of a statistical formula to a single individual is questionable, in this procedure, we compare the evolution of hearing over the years for the same individual. It therefore eliminates the factor of individual sensitivity to noise for subjects who are classified as otologically normal. For subjects having pathologies that may influence the evolution of hearing, the same procedure can be used according to Annex B of the ANSI S3.44 standard. RATIONALE Over the years, costs for compensation for ONIHL have been increasing. A review of compensation costs from 1973 to 2003 demonstrates ever-increasing mandatory awards. 1 American Academy of Otolaryngology Head and Neck Surgery Foundation, Inc.: Evaluation of People Reporting Occupational Hearing Loss, 1998, p.37 2 ANSI S (R2006) Determination of Occupational Noise Exposure and Estimation of Noise- Induced Hearing Impairment (with Erratum) 1

2 Figure 1 Maximum compensation of ONIHL in the United States for various States, federal employees and Longshoremen for a 30-year period No. of states Average maximum costs US$ 12,645 35,981 59,531 73,040 Federal employees US$ 100, , , ,912 Longshoremen US$ 33, , , ,040 Table 1 Continuous increasing maximal compensation benefits for hearing loss over that 30 year period in the U.S. Figure 2 Projections of average maximal compensation costs for ONIHL in US$. 2

3 When the employee makes a claim for ONIHL, it is with his current employer. ACQUISITION OF ONIHL It is important to determine what part of the hearing loss can be attributed to the current employer. In the scientific approach developed, acquisition of ONIHL is based on the ANSI S3.44 formulas. An example is presented of what would be the responsibility of previous employers for a 50-year-old male who has worked for 10 years in three different companies at the same noise level of 92 dba. Figure 3 Graphic example of allocation base on sequential order of exposure for an employee who worked for the amount of time at same level of exposure for 3 companies The analysis is as follows: Company #1 Company #2 Company #3 Exposure 10 years 92dBA 10 years 92dBA 10 years 92dBA NIPTS.5123K 50% 4.5dB 1.3dB 0.8dB age: 50 years % of responsibility 68% 20% 12% Table 2 Hearing loss in db based on the American Medical Association compensation standard and percentage of responsibility at the.5 percentile of ANSI S3.44. A graphic presentation of this scientific calculation demonstrates the liability of each employer in relation to the acquisition of ONIHL in a sequential order. A frequently used procedure is to allocate responsibility according to the time spent with different companies. In the following example from a scientific approach, this procedure is not valid. 3

4 Figure 4 Example of acquisition of ONHIL in relation to duration of employment with 2 different employers. In certain States, exposure to non-occupational hearing loss can reduce the compensation claims. Figure 5 Allocation between occupational and non-occupational exposure to noise. In the presence of non-occupational exposure to noise, if the levels are known, in States where part of the liability can be attributed to the socioacousis aspect, the 4

5 developed approach allows to determine which portion of the hearing loss should be attributed to ONIHL and non-occupational hearing loss. The details of the calculation are presented in Table 3, taking into consideration both the number of hours where a worker is exposed to occupational noise and the number of hours per week exposed to non-occupational noise. Company A B C Duration of exposure (years) Average TWA Occupational Non-occupational NIPTS (50%) Occupational Non-occupational Allocation for period Occupational Non-occupational 92dBA/8h/day 92dBA/6h/week % 5% 92dBA/8h/day 92dBA/6h/week % 2% 92dBA/8h/day 92dBA/6h/week % 3% Table 3 Representation of the hearing loss attributed to both occupational and nonoccupational exposure to noise. If non-occupational to noise can be documented, the proportion of hearing loss attributed to the socioacousis aspect can also be evaluated. An example of a non-occupational exposure is presented. A 41-year-old male, working as a truck driver for 15.6 years, made a claim for ONIHL. Figure 6 Example of non-occupational allocation. 5

6 Based on this occupational exposure to noise, according to the predictions of ANSI S3.44 from the.9 to.1 fractile, as shown in the graphic, there is no relationship with the observed hearing loss and the predictions. This kind of disparity between the predictions should induce a greater evaluation to establish the cause of this disparity whether from non-occupational exposure to noise or other causes such as pathologies. As a first step, considering his noise level exposure, the predictions of hearing loss according to ANSI S3.44 are presented in a graphical form. The graphic presentation consists of the prediction from the.9 to.1 percentiles. As can be seen in the graphic presentation, there is no correlation of the actual hearing loss with the predictions of ANSI S3.44. Upon investigation, it was found that this truck driver worked approximately 3 evenings of week for several hours as a professional disc jockey with excessive noise exposure. Following this demonstration of non-occupational exposure to noise, a revised evaluation of the costs attributed to occupational noise exposure was done with the resulting economic savings. Figure 7 Savings due to the identification of non-occupational exposure to noise as a disc jockey for a 41-year-old truck driver. FINANCIAL CONSIDERATION The review of medical claims in mining companies for a period of 15 years demonstrates an important saving based on the following aspects: Review of medical claims Allocation of responsibility Adequate hearing conservation program 6

7 Figure 8 Saving analysis As director of the hearing conservation programs for the mining industries, the medical review proved beneficial in the early years. RECOMMENDATIONS At present, in industry it is recommended to review claims using the following procedure: Sequential exposure to noise with various employees or according to various tasks in occupation with each employee Evaluate the non-occupational exposure to noise when indicated Medical review of claims in relation to personal pathologies that may have influenced the evolution of hearing Inclusion of the age factor when indicated These services can be provided with medical review by qualified otologists and statistical personnel to determine on a scientific basis the attribution of responsibility according to either Annex A of ANSI S3.44 for otologically normal subjects or Annex B of ANSI S3.44 for the inclusion of all employees. 7