Noise exposure and hearing loss in agriculture: a survey of farmers and farm workers in the Southland region of New Zealand.

Farmers are known to be exposed to intermittent intense noise from a variety of sources, but long-term exposure and the resulting risk of hearing loss have not been well characterized. We studied a cross-sectional random sample of farms on which agricultural workers completed an audiometric test and questionnaire, and performed noise dosimetry on a subsample. Sixty-five percent of farms and a total of 586 workers participated. Noise on the subsample of 60 farms lay in a range between 84.8 to 86.8 dB(A) and hearing losses were consistent with this level of exposure. Age, driving tractors without cabs, and working with metal were important risk factors. Reported compliance with hearing protection was higher than that actually observed. The majority of farmers have a moderate risk of hearing loss, but a significant minority is at high risk. Elimination and isolation of noise sources are the control methods of choice, and if residual hearing protection is required, compliance must be improved.