This study evaluated the ototoxicity by mixed organic solvents on workers'hearing using the upper limit of hearing(ULH).

Seven hundred ninety-seven male workers in the ship building industry who were evaluated by interview with an upper limit of hearing from August 2000 to July 2002 were enrolled in the study. The subjects were divided into 3 groups according to exposure profile and job: officers, field supporters, and painters. To assess the ototoxicity of mixed organic solvent exposure on hearing, with regard to confounders, the general liner model was used.

After controlling for the possible confounders, such as age, career, noise exposure level, tinnitus, alcohol intake, and smoking, the estimated mean for ULH of the painter group was higher than that of the officer and the field supporter groups. These differences of mean ULH were at the borderline of statistically significance(p=0.069).

The results of this study suggest that a relatively lower level of mixed organic solvent chronically affected the hearing organ or auditory pathway. ULH seems to be a useful method for early detection of the ototoxicity of organic solvents.