OELs (AGW) for chemical substances in workplace air are derived or evaluated by the Committee on Hazardous Substances (Hazardous Substances Commission, Ausschuss für Gefahrstoffe – AGS) according to the criteria of the BekGS 901 „Kriterien zur Ableitung von Arbeitsplatzgrenzwerten“ (GMBl. 2010, No. 32, p. 691) and published in the TRGS 900. The AGS evaluates OEL proposals from the following sources:

• The MAK values of the DFG Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area (DFG: German Research Foundation)
• The indicative OELs of the European Commission
• International limit values (e.g. from the Netherlands)

MAK values (Maximum Concentrations at the Workplace) and BAT values (Biological Tolerance Values) promote the protection of health at the workplace. They are an efficient indicator for the toxic potential of chemical compounds:

• The MAK value (“maximale Arbeitsplatz‐Konzentration”: maximum workplace concentration) is defined as the maximum concentration of a chemical substance (as gas, vapour or particulate matter) in the workplace air which generally does not have known adverse effects on the health of the employee nor cause unreasonable annoyance (e. g. by a nauseous odour) even when the person is repeatedly exposed during long periods, usually for 8 hours daily but assuming on average a 40‐hour working week. MAK values are given in ml/m³ (ppm) and/or mg/m³.
• The BAT value describes the occupational‐medical and toxicological derived concentration for a substance, its metabolites, adducts or an effect parameter in the corresponding biological material at which the health of an employee generally is not adversely affected even when the person is repeatedly exposed during long periods. BAT values are given in a number of similar units including ug/l, mg/g, mg/l, ug/g.

In accordance with the German Ordinance on hazardous substances (GefStoffV), the employer must ensure that the workplace exposure limits are complied with at work. However, a workplace exposure limit cannot currently be derived for the vast majority of carcinogenic substances. For this reason, the Committee on Hazardous Substances (AGS) established an overall concept for setting risk-based limit values for carcinogenic substances (TRGS 910). The risk-based values are based upon a working lifetime of 40 years and continuous exposure every working day. The concept is closely related to a concept of graduated measures for minimizing risk in the workplace. Substance-specific concentration figures derived from well-founded exposure-risk models are compiled in TRGS 910 and should be taken into account by the employers during their risk assessment.

**For more information specific to this country, please refer to the relevant in-country guidance.**