Field Study to Explore Possible Effects of Styrene on Auditory Function in Exposed Workers

Objectives: We conducted this study to examine, whether occupational styrene exposures are associated with reduced hearing ability. Methods: The auditory function was investigated by pure tone audiometry and registration of transitory evoked otoacoustic emissions (TEOAE) in 32 workers of a fibre-reinforced plastic boat building factory. Sixteen subjects were laminators (mean age: 41yr (SD: 8)) and therefore regularly exposed to styrene with mean duration of exposure to styrene of 7.5yr (SD 5.0). The tests were applied to a reference group of 16 workers (mean age: 39yr (SD: 8)) who were not directly exposed to styrene but had a similar noise exposure. Results: A few and isolated correlations between the parameters of hearing acuity and exposure indices, such as current internal styrene exposures (sum of MA and PGA) and duration of styrene exposure, were statistically significant, but no consistent association was found. Conclusion: The results of this study do not support the assumption of an ototoxic effect of chronic styrene exposure in workers.