HEARING-LOSS FROM COMBINED EXPOSURES AMONG PETROLEUM REFINERY WORKERS

Workers from a refinery (n=438) were interviewed, had their hearing te sted and had their exposures to noise and solvents assessed. Measureme nts suggested that most exposures to noise and solvents were within ex posure limits recommended by international agencies; however, the prev alence for hearing loss within the exposed groups ranged from 42 to 50 %, significantly exceeding the 15-30% prevalence observed for unexpose d groups. The adjusted odds ratio estimates for hearing loss were 2.4 times greater for groups from aromatics and paraffins (95% CI 1.0-5.7) , 3 times greater for the maintenance group (95% CI 1.3-6.9) and 1.8 t imes greater for the group from shipping (95% CI 0.6-4.9), when compar ed to unexposed workers from the warehouse and health clinic. The resu lts of acoustic reflex decay tests suggest a retrocochlear or central auditory pathway involvement in the losses observed in certain job cat egories. These findings indicate that factors in addition to noise oug ht to be considered when investigating and preventing occupational hea ring loss.