Background. In 1987, workers employed at the Anniston Alabama Army Depot (ANAD) were enrolled in a hearing conservation program based on an 85 dBA criterion level for an 8-hour day with a 5 dB exchange rate. Under these criteria, 500-700 employees were removed from the program. In 2001, these employees were re-enrolled in the hearing conservation program because of a Department of the Army mandate that exposures be measured with a 3 dB exchange rate and if the 95% upper tolerance limit for measured exposures were above 85 dBA. A previous study has determined that workers at the ANAD who were removed from the hearing conservation program in 1987 and re-enrolled in 2001 did not experience significant changes in hearing sensitivity due to occupational noise, nevertheless there were significant changes in hearing sensitivity in this group (Norman, 2005). The purpose of this study was to determine what factors were associated with measured hearing levels in this group in 2001. Methodology. The study population was defined as: a worker who was employed by the ANAD from January 1987 until January 2001; the worker was removed from the hearing conservation program in 1987 and re-enrolled in 2001; the worker had an audiogram ± 1 year of January 1, 2001; the hearing threshold level for either ear was ≥ 25 dB; and the worker completed a questionnaire concerning medical history, military noise exposures, home and recreational noise exposures, and non-noise occupational exposures. The association between the responses to questions and measured hearing sensitivity in 2001 was tested by linear regression and principal component analysis. Results. Forty three participants met the criteria to be included in the study. The linear regression model found a significant association between measured hearing levels, age, and military weapons fire. Results of the principal component analysis indicated military weapons fire and recreational hunting significantly affected measured hearing levels.

Conclusions. Hearing threshold levels among Anniston Army Depot workers in 2001 were significantly associated with non-occupational noise exposure factors but were not associated with non-noise occupational exposure factors. These results concur with results of previous studies.