Abstract
Methoxyacetic acid
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) of 1 ml/m3 for methoxyacetic acid, considering the endpoints local and systemic toxicity as well as developmental toxicity. Methoxyacetic acid acts locally as well as systemically. It is the metabolite responsible for the haematotoxicity and reproductive toxicity of the better investigated methoxyethanol. Hence, the MAK value of 1 ml methoxyethanol/m3 was also assigned to methoxyacetic acid in 2008. A 28‐day study with rats shows a NOAEC for systemic and local effects of 15 ml/m3. 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. According to this approach, a concentration of 0.9 ml/m3 for the workplace air can be calculated from this study. Therefore, the MAK value of 1 ml/m3 is confirmed. Systemic as well as local effects are critical and the assignment to Peak Limitation Category II for systemic effects is retained. However, to avoid sensory irritation, the former excursion factor of 8 seems too high and is reduced to 2 in analogy to the excursion factors for formic and acetic acid. The assignment to Pregnancy Risk Group B, substances for which damage to the embryo or foetus cannot be excluded even when the MAK value is observed, is confirmed.
Hartwig, A