Submission to Federal Minister of Labour / 85 supplements and new entries / New assessments for indium and other substances

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 59th List of Maximum Workplace Concentrations (MAK values) and Biological Tolerance Values (BAT values). The list has now been 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. Recognising the crucial scientific significance of the Senate Commission’s work, the DFG Senate previously approved the MAK Commission's mandate extension for another six years in December 2022.

The current list contains 85 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 active occupational health and safety at the international level. The current list specifically contains 16 new MAK and BAT values. One of these that is particularly worthy of mention is the review and lowering of a MAK value for ε-Caprolactam, an important raw material used in the production of plastics such as nylon. Furthermore, the assessment of the metal indium and its inorganic compounds was completed. The latter are important for technical applications in the electronics industry. Indium and its inorganic compounds were found to be carcinogenic based on inflammation and tumours in the lungs of rats and mice that had inhaled the substance. It has not yet been possible to derive a health-based occupational exposure limit based on the existing data, however.

For the substance diethylene glycol monomethyl ether (DEGME), which among other things is used as an antifreeze in aviation fuel, a BAT value was also derived for the parameter methoxyacetic acid. Methoxyacetic acid has a developmental toxic effect on unborn babies even if the MAK and BAT values are observed. In order to protect the unborn, therefore, a urine concentration was derived for pregnant women at which a teratogenic effect is not to be assumed.

Following on from the Commission’s ongoing engagement with new methodological approaches – in order to ensure a high level of scientific quality in the testing of harmful agents – the Commission published a statement entitled New Approach Methods (NAMs) in der wissenschaftsbasierten Ableitung von Grenzwerten (“New Approach Methods (NAMs) in the science-based derivation of limit values”) in April 2023. The term “New Approach Methods” is used in connection with the risk assessment of chemicals at European and international level. In addition to studies on cell cultures, it includes various methodological approaches such as different forms of data integration and modelling. For this reason, NAMs also offer an opportunity to reduce the amount of animal experimentation and use existing data sets more systematically than before.

In its statement, the Commission emphasised that the increasing use of NAMs makes an important contribution to the 3R principle (Replace, Reduce, Refine) in research, enabling risk assessment to be significantly and effectively expanded in combination with conventional toxicological methods. At the same time, it pointed out that much research is still needed on the validation and scientific assessment of the possibilities and limitations of NAMs before animal-based research approaches for quantitative risk assessment can be done away with as a prerequisite for deriving 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 values). The list also contains biological guidance values (BLW values) and biological reference values (BAR values). The so-called exposure equivalents for carcinogenic substances (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. Proposals for supplements and new entries are open for discussion until 31 December 2023. 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. The internet platform is maintained by ZB MED, the central library for medicine, public health, nutrition, environmental and agricultural sciences in Germany. In addition to publishing the latest results of the Commission’s scientific work, the aim is to make all publications available in open access and present the findings for subsequent in-depth use.

Further information

For the 2023 list of MAK and BAT Values, open access MAK Collection publications and further information on the work of the Senate Commission, see:

• www.dfg.de/mak/en

To the statement New Approach Methods (NAMs) in der wissenschaftsbasierten Ableitung von Grenzwerten (“New Approach Methods (NAMs) in the science-based derivation of limit values”) (April 2023):

• www.dfg.de/download/pdf/dfg_im_profil/gremien/senat/arbeitsstoffe/ stellungnahme_nams_grenzwerte_en.pdf

Editorial offices may request a free review copy at:

• presse@dfg.de

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

• Dr. Gunnar Jahnke and Dr. Gerlinde Schriever-Schwemmer
  Tel. +49 721 608-47400
  mak_sekr@iab.kit.edu

Contact at DFG Head Office:

• Dr. Katja Hartig
  Life Sciences
  Tel. +49 228 885-2359
  arbeitsstoffkommission@dfg.de