Standards for dermal exposure at the workplace

Standards for occupational exposure to hazardous substances currently apply only to exposure via respiration. The standard is a numerical one in the form of a Maximum Allowable Concentration: the MAC value. The scientific basis for the MAC value is a risk assessment for the substance in question which leads to a recommended health limit, the Health Based Recommended Occupational Exposure Limit (HBR-OEL). If the risk assessment shows that exposure via the skin might also be important, a general warning is added to the MAC value to avoid contact in the form of the so-called “H” indication, also known as skin notation. This form has been chosen because the role of dermal exposure and protective measures to be taken depend to a large extent on the actual situation at the workplace and thus can best be assessed on site. Of the more than 650 MAC values, a quarter have a skin notation.