2,2'-Dichlorodiethyl ether: MAK Value Documentation, addendum - Translation of the German version from 2023

The German Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (MAK Commission) has re-evaluated the occupational exposure limit value (maximum concentration at the workplace, MAK value) for 2,2'-dichlorodiethyl ether [111-44-4] considering all toxicological end points. Relevant studies were identified from a literature search. In a study from 1933, 2,2'-dichlorodiethyl ether in concentrations of 100 ml/m³ and above showed irritating effects in humans. At 35 ml/m³ a clearly perceptible unpleasant odour was described and this concentration was irritating in guinea pigs. Reduced body weight gain was observed in rats in a chronic feeding study. This effect was more pronounced in female animals. In a combined repeated dose toxicity study screening also for reproduction/developmental toxicity in rats, the NOAEL for systemic effects was 15 mg/kg body weight and day, the highest dose tested. On this basis, the MAK value has been set at 0.5 ml/m³. As the critical effect of 2,2'-dichlorodiethyl ether is systemic, Peak Limitation Category II has been assigned with an excursion factor of 2. As substances with a higher irritation potency like monochloroacetic acid and 2-chloroethanol have similar or higher MAK values, the MAK value for 2,2'-dichlorodiethyl ether will also protect from irritation. Limited data show no genotoxic or carcinogenic potential for 2,2'-dichlorodiethyl ether. In a screening study, the NOAEL for perinatal toxicity in rats was 15 mg/kg body weight and day. As teratogenicity was not investigated, 2,2'-dichlorodiethyl ether has been assigned to Pregnancy Risk Group D. 2,2'-Dichlorodiethyl ether is not a skin sensitizer in a Local Lymph Node Assay in mice. According to skin absorption models, 2,2'-dichlorodiethyl ether is expected to be taken up via the skin in toxicologically relevant amounts. Therefore, 2,2'-dichlorodiethyl ether remains designated with "H".