Press Release No. 23 | July 1, 2021

Health and Safety at Work: DFG Senate Commission Presents 2021 List of MAK and BAT Values

DFG submits list to German Federal Labour Minister / 95 supplements and new entries / Threshold limit values established for lead

DFG submits list to German Federal Labour Minister / 95 supplements and new entries / Threshold limit values established for lead

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 presented the 57th List of Maximum Workplace Concentrations (MAK values) and Biological Tolerance Values (BAT values). The list was submitted to the Federal Minister of Labour and Social Affairs and serves as an essential scientific basis for changes and modifications of statutory regulations in the field of occupational health and safety. The list is prepared in fulfilment of the DFG’s mandate to provide scientific policy advice as stipulated in its statutes. This year the list contains 95 supplements and new entries. The digital version of the List of MAK and BAT values is available in German, English and Spanish in open access. In this way, the Commission also contributes to further development and active occupational health and safety at the international level.

In the current list, the Commission has arrived at new assessments for lead and its inorganic compounds. Mainly as a result of the ban on leaded petrol, the exposure of the general population to lead in industrialised countries has decreased significantly in recent decades; this is also noticeable in continuously decreasing levels of lead in blood. Lead continues to be a major problem at the workplace, however. Based on new findings on carcinogenic effects and organ damage caused by lead, it was possible to change the previous classification from carcinogenicity category 2 (carcinogenic in animal experiments, no threshold limit value possible) to category 4 (carcinogenic, mechanism known, threshold limit value evaluable). As a result it was possible to derive a BAT value of 150 µg/l blood for lead. Compliance with this ensures protection from both the carcinogenic effects and the most sensitive toxic effects, namely damage to the nervous system.

Lead absorbed into the body is stored in the bones for many years and is detectable in blood. In the case of lead, it is not possible to make simple conversions from concentrations in the air at the workplace to concentrations in the blood of employees. By means of complex mathematical modelling, however, it was possible to inversely derive a MAK value of 0.004 mg/m3 from the BAT value. Due to the adverse effect of lead on the developing nervous system, however, a risk to an unborn child must be assumed even if the BAT or MAK value is complied with; therefore, lead has been assigned to pregnancy group A.

In order to ensure a high level of scientific quality in the testing of harmful agents, the Commission regularly updates its procedures. For this reason, two new text passages were introduced in Section I of the List of MAK and BAT values. One of these concerns the application of the MAK values designed for eight hours in cases where working hours are regularly longer. The other is a fundamentally revised and supplemented passage on the handling of odour-intensive working substances when setting threshold limit values.

The so-called List of MAK and BAT Values contains not just the eponymous MAK values – (maximum workplace concentrations), i.e. the amount of substances that may be present in the workplace in the form of gas, vapour or aerosol without causing long-term damage – it also 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 (BAT values – the biological tolerance value). The List of MAK and BAT value also contains biological guidance values (BLW values) and biological reference values (BAR values). The so-called exposure equivalents for carcinogenic agents (EKA) can be used to determine the internal exposure that would result if a substance were ingested exclusively via the respiratory tract.

Detailed scientific justifications are available for each of the substances reviewed, transparently outlining the Commission’s decision-making processes. Proposals for supplements and new entries are open for discussion until 31 December 2021. Until then, new data or scientific comments can be submitted to the Commission’s Scientific Secretariat.

All substance justifications and methodological descriptions prepared by the Commission along with the annually published List of MAK and BAT values are to be found in the MAK Collection for Occupational Health and Safety. ZB MED is currently working to complete the new internet platform. In addition to the latest results of the Commission’s scientific work, this will make all publications available in open access and findings will be presented for subsequent in-depth use.

Further Information

For the list itself including all new additions and changes to the 2021 List of MAK and BAT Values, for open access MAK Collection publications and for further information on the work of the Senate Commission, see:

Editorial offices can request a free review copy at:

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

Contact at the DFG Head Office: