Press Release No. 31 | September 23, 2020

Health and Safety at Work: DFG Senate Commission Publishes English Version of 2020 List of Maximum Workplace Concentrations and Biological Tolerance Values

Total of 65 supplements and new entries / Solvent 1,2-dichloropropane and gadolinium contrast agents

Total of 65 supplements and new entries / Solvent 1,2-dichloropropane and gadolinium contrast agents

The Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) has published the English version of the 56th List of Maximum Workplace Concentrations (MAK values) and Biological Tolerance Values (BAT values). The German list was submitted to the Federal Minister of Labour and Social Affairs in July. This publication serves as an essential basis for necessary changes and modifications to occupational safety legislation. The DFG prepares this document in fulfilment of its mandate to provide scientifically based policy advice as stipulated in its statutes. This year, the list includes 65 supplements and new entries, and it is available in a printed version as well as in digital open access format. The digital list is published in German, English and Spanish, allowing the Commission to contribute to ongoing development and the active protection of health and safety at international level.

In the updated list, the Commission has specified a carcinogenicity category of "carcinogenic to humans" for 1,2-dichloropropane. This is a widespread solvent used for cleaning which takes a long time to break down in the environment. In Japan, several printing company employees contracted bile duct cancer, a normally rare type of cancer in humans, after using 1,2-dichloropropane as a solvent – despite the fact that this had not occurred in animal testing. For substances that are carcinogenic to humans no health-based limit can be defined, but a classification in this regard has far-reaching implications for practical occupational safety, which are defined by the Committee on Hazardous Substances (AGS) of the Federal Ministry of Labour and Social Affairs.

The Commission also turned its attention to gadolinium, a type of rare-earth metal. It is used in compound form in the contrast agents used for magnetic resonance imaging. Recently, there has been discussion surrounding the occurrence of signs of poisoning caused by gadolinium contrast agents following MRI scans. However, no concrete statements can be made based on the currently available data. Gadolinium is excreted in urine and has been detected in water bodies and in some cases in drinking water. Although the data is currently insufficient to define an assessment value in blood or urine, from the aggregation of information available so far on the background level of the general population it is possible to estimate whether individuals show clearly increased gadolinium exposure following administration of a contrast agent.

As well as the eponymous maximum workplace concentrations (the amount of a substance that may be present in the workplace in the form of a gas, vapour or aerosol without causing long-term damage), the list of MAK and BAT values contains information about which substances are carcinogenic, damage germ cells or harm a developing foetus during pregnancy, sensitise the skin or respiratory tract, or are absorbed through the skin in toxic amounts. It also reports the concentration of a substance in the body to which a person can be exposed for a working lifetime without experiencing adverse health effects (the biological tolerance value). Furthermore, it describes the biological guidance values (BLW values), the exposure equivalents for carcinogenic substances (EKA values) and the biological reference values (BAR values).

For each of the reviewed substances there is detailed scientific documentation that makes the Commission's decision-making processes transparent. The proposals for the supplements and the new entries are available for discussion until 31 December 2020. New data and scientific comments can also be submitted to the Commission's Scientific Secretariat up to that date.

The annually published MAK and BAT values lists, as well as all of the justifications and method descriptions prepared by the Commission, are available in the MAK Collection. A new platform is currently being built for the MAK Collection by ZB MED Information Centre for Life Sciences to facilitate and further develop scientific work with the Commission's results. The first publications have already been made available on the new platform.

Further Information

List of Maximum Workplace Concentrations and Biological Tolerance Values 2020:

A detailed list with all new entries and supplements to the list of MAK and BAT values, access to the open access publications of the MAK Collection and further information on the work of the Senate Commission can be found at:

Editors may request a free copy for review purposes from

  • DFG’s Press and Public Relations Office,
    Tel. +49 228 885-2109,

Scientific Secretariat of the DFG Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area:

  • Dr. Gunnar Jahnke 
    Dr. Gerlinde Schriever-Schwemmer, 
    Tel. +49 721 608-47400, 

DFG Head Office contact: