Glycerin [MAK Value Documentation, 2016]

Abstract The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the work place (MAK value) of glycerol [ 56‐81‐5 ], considering the endpoints irritation of the respiratory tract and developmental toxicity. Since 2014, the Commission uses an empirical approach to set MAK values for substances with critical effects on the upper respiratory tract or the eyes. However, examination of the study results showed that this approach does not apply for glycerol, because glycerol is not an eye irritant and the minimal to slight metaplasia of the squamous epithelium of the larynx seen in rats at 662 mg/m 3 with glycerol aerosol is not interpreted as adverse. The response does not increase with the exposure duration. Therefore, the MAK value is raised to 200 mg glycerol/m 3 for the inhalable fraction. Peak Limitation Category I for local effects with an excursion factor of 2 is retained, as the effect is hardly concentration‐dependent, a sensory irritation is not known, and glycerol is, if at all, only slightly irritating to the eye. After scaling the oral NOAELs for developmental toxicity of 1310, 1280 and 1180 mg/kg body weight and day for rats, mice, and rabbits, respectively, to a concentration at the work place (2293, 1280, and 3442 mg/m 3 ), the differences to the MAK value are considered so large, that there is no reason to fear damage to the embryo or foetus when the MAK value is observed. The classification in Pregnancy Risk Group C is therefore retained.