Genetic effects of occupational exposure to styrene as measured using the micronucleus test

Styrene has been shown to be mutagenic upon metabolic activation. However, studies of occupationally exposed populations have shown conflicting results when looking for chromosomal effects. The present study was conducted to help determine the chromosomal effects of occupational exposure to styrene. Lymphocyte micronuclei were used as indicators of chromosomal breakage. Eight exposed subjects involved in fiberglass fabrication and six matched controls from a metal fabrication company were studied. Styrene exposure was measured using an infrared analyzer and passive organic vapor monitors. Actual styrene dosage and metabolism was documented with end-of-shift urinary mandelic acid measurements. Lifetime styrene exposure was calculated from questionnaire data. Micronuclei were counted in lymphocytes with intact cytoplasm. The exposed subjects showed an increase in lymphocyte micronuclei, but the increase was not statistically significant. No dose response relationship was found between current styrene exposure and micronucleus levels, mandelic acid and micronucleus levels, or lifetime styrene exposure and micronucleus levels.