Long-Term Exposure to Dimethylformamide in Artificial Leather Manufacturing

Abstract

A 1-year survey was conducted in three polyurethane leather factories where workers were exposed to dimethylformamide. N-Methylformamide (NMF) was monitored in urine specimens collected monthly at the end of a shift. The following parameters were calculated: the geometric mean (GM) and geometric standard deviation (GSD) as indicators of average annual NMF concentrations in the urine of workers in each factory and day-to-day variation of the average; the probability of noncompliance with the reference values [biological exposure indices (BEIs)] during the unmonitored periods [according to National Institute for Occupational Safety and Health (NIOSH) recommendations]; and the number of working days in which the exposure limit was likely to be exceeded. NMF concentrations in the urine of workers in the factory using the coagulate system (GM ± GSD = 29.45 ± 1.26 mg/g of creatinine) were significantly higher than NMF concentrations in urine collected in two factories using the transfer system (9.53 ± 1.5 and 3.32 ± 1.98 mg/g of creatinine, respectively). In the coagulate system, a polyurethane mixture impregnates a fabric in foulard tanks; in the transfer system, a polyurethane mixture is spread onto a transfer paper, dried, and coupled to a fabric. The probability of noncompliance with the current BEI of 40 mg NMF/g creatinine) was 9.7 percent in the factory using the coagulate system, whereas the probability of noncompliance was practically nil in the two factories using the transfer system. The authors recommend the use of long-term biological measurement to verify the effect of different manufacturing processes on the level of workers exposure and to underscore the usefulness of the NIOSH scheme applied to biological instead of environmental data. Catenacci, G.; Pezzagno, G.; Marraccini, P.; Saretto, G.: Long-Term Exposure to Dimethylformamide in Artificial Leather Manufacturing.