Nitroethan [MAK Value Documentation in German language, 2017]

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) for nitroethane [79‐24‐3], considering the endpoints local and systemic toxicity as well as developmental toxicity. Nitroethane acts locally as well as systemically. A 13‐week study in rats and mice found significantly increased methaemoglobin levels accompanied by changes in the spleen as critical effects. A NOAEC was not obtained. Based on the LOAEC of 100 ml/m3 and taking into consideration the higher sensitivity of humans and the possibility of effects increasing with time, the MAK value for nitroethane is lowered to 10 ml/m3. Degeneration, inflammation and hyperplasia of the olfactory epithelium occur at higher exposure concentrations. As the critical effect is systemic, the assignment to Peak Limitation Category II is retained as well as the excursion factor of 4. Because there are no studies on developmental toxicity with pure nitroethane, the assignment to Pregnancy Risk Group D is also confirmed. Skin contact may contribute significantly to systemic toxicity and nitroethane is designated with an “H”. Sensitization is not expected from the limited data