The Derived Minimal Effect Level (DMEL) for Enzymes in Industrial Practice.

Twenty years ago the European Union introduced regulations known as REACH (Registration, Evaluation, Assessment and restriction of Chemicals). Amongst other things, these required a defined minimum effect level (DMEL) for respiratory allergens. A DMEL of 60 ng/m3 was established for industrial enzymes as the starting point for risk management/occupational hygiene. In the present work, an 11-year set of airborne exposure measurements and employee health information was harvested from three enzyme-producing factory locations in Denmark which use this DMEL as their starting point/action standard. Air sampling data (approximately 45000 points) demonstrated good exposure control. More than 42000 measurements met the standard; only 6.0% exceeded the 60 ng/m3 limit, many by only a modest margin, but which served as a trigger for action. The associated occupational health information confirmed employee health was well controlled, with rates of enzyme sensitisation at 1.2%, and expression of symptomatic allergy kept to a minimal 0.3%. Of the 8 employees with allergy symptoms, 7 continued in their employment, mostly for several years, free of disease. This outcome is consistent with previous reporting and with proper occupational health management, designed to achieve "minimum effect" and thus substantiates the longstanding adoption of the industrial enzyme DMEL of 60 ng/m3.