Peracetic acid
MAK Value Documentation, addendum – Translation of the German version from 2021
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 Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission) summarized and re-evaluated the data for peracetic acid [79-21-0] to derive an occupational exposure limit value (maximum concentration at the workplace, MAK value) considering all toxicological end points. Relevant studies were identified from reviews, a literature search and also unpublished study reports were used. Peracetic acid is commercially available only in aqueous solutions, in which it exists in equilibrium with hydrogen peroxide and acetic acid. Therefore, all three substances contribute to toxicity. No specific systemic effects were observed, which is plausible because peracetic acid immediately oxidizes the tissues at the point of contact and is thereby converted to acetic acid. Peracetic acid is a promotor of skin tumours in mice. Valid long-term carcinogenicity studies with peracetic acid, particularly studies using an inhalation route, are not available. The mechanisms by which peracetic acid may induce carcinogenic effects are, as has already been demonstrated for hydrogen peroxide, local cytotoxicity leading to tissue damage and genotoxicity; both are due to the strong oxidation potency. These mechanisms do not come into play unless the endogenous detoxification capacities are overloaded. Due to this mechanism of action, hydrogen peroxide was classified in Carcinogen Category 4. As the same mechanism is likewise plausible for peracetic acid, it has also been classified in Carcinogen Category 4. Peracetic acid is the strongest irritant of the substances in the equilibrium mixture. If sensory irritation is excluded, it is also ensured that the detoxifying enzymes are not overloaded and thus neither tissue-damaging nor genotoxic effects occur. Based on the RD50 for pure peracetic acid in mice of 4.6 ml/m3, the maximum concentration at the workplace (MAK value) for peracetic acid is set at 0.1 ml/m3. The available human data are not sufficient to derive a MAK value, but do not contradict it either. As the critical effect of peracetic acid is local, Peak Limitation Category I has been designated. By analogy with hydrogen peroxide and as the data for the human experience with peracetic acid are of only limited validity, an excursion factor of 1 has been set. The few positive results for genotoxicity in vitro obtained with peracetic acid occurred at cytotoxic concentrations or in the absence of detoxification systems. All valid in vivo genotoxicity tests were negative, but the significance of the negative test results is questionable since peracetic acid induces a rapid local reaction. Therefore, it can also be concluded that classification in a category for germ cell mutagens is not required. The NOAEL for developmental toxicity in rats is 30.4 mg/kg body weight and day, which corresponds to a concentration of 53 mg/m3 at the workplace. Therefore, damage to the embryo or foetus is unlikely when the MAK value is not exceeded and peracetic acid is assigned to Pregnancy Risk Group C. Skin contact is expected to contribute only slightly to systemic toxicity. With respect to skin sensitization, there are no positive findings in humans and no reliable positive findings in animals. The respiratory symptoms that occur in exposed workers are caused by irritation.
