Maleic anhydride
MAK Value Documentation, supplement – Translation of the German version from 2018
Andrea Hartwig1 (Chair of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)MAK Commission2
1 Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Building 50.41, 76131 Karlsruhe, Germany
2 Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft, Kennedyallee 40, 53175 Bonn, Germany
Abstract
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re-evaluated maleic anhydride [108-31-6], considering all toxicological end points. Available publications and unpublished study reports are described in detail. Maleic anhydride is an irritant to the upper respiratory tract. A LOAEC of 0.27 ml/m3 for nasal and ocular irritation was obtained from a 6-month inhalation study in rats, hamsters and monkeys. Since 2014 the Commission uses an empirical approach to set the maximum concentration at the workplace (MAK value) for substances with critical effects on the upper respiratory tract or the eyes. Based on this, the MAK value for maleic anhydride is set at 0.02 ml/m3 (0.081 mg/m3). Since the critical effect of maleic anhydride is local, Peak Limitation Category I with an excursion factor of 1 is confirmed and a momentary value of 0.05 ml/m3 is set. Damage to the embryo or foetus is unlikely when the MAK value is not exceeded and maleic anhydride remains assigned to Pregnancy Risk Group C. Maleic anhydride is not genotoxic in vitro and in vivo. No increased tumour incidence was observed in a chronic feeding study in rats. Skin contact is not expected to contribute significantly to systemic toxicity. In humans, airway sensitization is observed. There are positive results of contact sensitization in mice and guinea pigs. Maleic anhydride continues to be designated with “Sah”.
