N‐Methyl‐2‐pyrrolidone (vapour)

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) of N‐methyl‐2‐pyrrolidone [872‐50‐4]. The critical effects in rats are irritation of the upper respiratory tract, foetotoxicity and neurotoxicity. Male volunteers did not show adverse irritant or cognitive effects after 8‐hour exposure to N‐methyl‐2‐pyrrolidone at a concentration of 20 ml/m3 with and without exposure peaks of 40 ml/m3 and with physical workload. A MAK value of 20 ml/m3 had been set for N‐methyl‐2‐pyrrolidone vapour. This value has now been confirmed even considering the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c). Exposure to N‐methyl‐2‐pyrrolidone aerosols increases the intake by dermal absorption but there is no information indicating by how much. Therefore, the MAK value is only valid for the vapour of N‐methyl‐2‐pyrrolidone and exposure to aerosols or vapour/aerosol mixtures must be controlled by biomonitoring methods. As the critical effect of N‐methyl‐2‐pyrrolidone is assumed to be local, Peak Limitation Category I has been designated. The excursion factor of 2 is retained.