Liver function alterations in synthetic leather workers exposed to dimethylformamide.

A cross-sectional study of the prevalence of chronic liver function alterations was performed in 75 workers employed in a synthetic leather factory, exposed to dimethylformamide (DMF) air concentrations below threshold limit values (30 mg/m3). Biological monitoring among workers revealed acceptable urine levels of monomethylformamide (NMF) on average, but the very wide range indicated that occasional overexposure was possible. The worker survey showed a high percentage of disulfiram-like symptoms (50%) and liver function abnormalities (22.7%), compared with a demographically similar group of unexposed workers. Covariance analysis (ANCOVA) revealed that enzyme levels were significantly higher in exposed workers than in controls after data were corrected for age, alcohol consumption, body mass index, and cholesterol levels. The authors conclude that DMF can cause liver diseases even if air TLVs are respected, because accidental contact with liquid DMF can significantly increase DMF uptake. In this situation, air monitoring is no longer sufficient to evaluate worker exposure.