Maximum workplace concentration

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The maximum workplace concentration ( MAK value ) indicates the maximum permissible concentration of a substance as gas , vapor or suspended matter in the (breath) air at the workplace . The values ​​set in each case are a compromise in weighing up possible damage to health (whereby shift work must also be taken into account) and the risks and costs of production. The MAK values ​​are “not constants from which the occurrence or absence of effects in the event of longer or shorter exposure times can be calculated.” As a result of technical progress, the corresponding values ​​have to be adjusted or reduced.


A list of the MAK values ​​together with the BAT values ​​and suggestions for changes are compiled and published by the “Senate Commission for the Testing of Substances that are Harmful to Health” in the German Research Foundation (DFG).

With the entry into force of the new German Hazardous Substances Ordinance ( GefStoffV ), an additional limit value concept has existed in Germany since January 1, 2005 . In the GefStoffV a distinction is made between occupational exposure limit values ( AGW) and biological limit values (BGW). The current Technical Rules for Hazardous Substances ( TRGS ), in particular the TRGS 900 "Occupational Exposure Limits" as of August 4, 2010 and the TRGS 903 "Biological Limits Values" as of December 2006, must therefore be applied in Germany. The designations MAK value and BAT value are still used in Germany by the “Senate Commission for the Examination of Hazardous Substances”. This Senate Commission publishes its proposals on July 1st every year. The suggestions are then checked by the Committee for Hazardous Substances (AGS) and, if necessary, incorporated into the Hazardous Substances Ordinance . The legally binding announcement of the limit values ​​takes place in the TRGS 900 occupational exposure limit values . If there is no occupational exposure limit set according to TRGS 900 for a substance in Germany, according to TRGS 402, e.g. B. the MAK value of the DFG can be used.

The list of MAK and BAT values ​​appears in German, since 1985 in English and since 2018 in Spanish.


The maximum concentration in the workplace is "the maximum permissible concentration of a work substance ... which, according to the current state of knowledge, does not generally impair the health of employees, even with repeated and long-term exposure, and does not inappropriately annoy them (e.g. by a nauseating smell ). ”The MAK values ​​apply to people who are healthy and of working age.

The MAK values ​​are usually adjusted downwards and published annually by the permanent “Senate Commission for the testing of hazardous substances”. When establishing the MAK values, the toxicological characteristics of the working materials are primarily taken into account. When establishing MAK values, "scientifically founded criteria for health protection, not the technical and economic possibilities of implementation in practice" are decisive. The MAK Commission bases the derivation of MAK values ​​on the NOAEL (No Observed Adverse Effect Level) for the most sensitive endpoint with health relevance of a substance.

As a rule, the actual concentration of foreign matter will never be completely constant, but rather be subject to fluctuations, which in many cases must not exceed a peak value. The substances are therefore assigned substance-specific exceedance factors (ratio of short-term permitted concentration peaks to the MAK value). The definitions of the exceedance factors can be found in Section VI of the list.

Each working substance is also assessed and classified with regard to the following characteristics:

  • Carcinogenicity (see Section III of the MAK list)
  • Germ cell mutagenicity (see Section IX of the MAK list)
  • Risk to pregnancy (see Section VIII of the MAK list)
  • sensitizing effect (see Section IV of the MAK list)
  • Contribution to systemic toxicity after skin absorption (see Section VII of the MAK list)

Assessment of carcinogenicity and germ cell mutagenicity

Section III of the MAK list contains the rules for the classification and evaluation of (potentially) carcinogenic substances. It is divided into five categories, from “substances that cause cancer in humans and which can be assumed to contribute to the risk of cancer” (Category 1) to “substances that cause cancer in animals or humans or are to be regarded as carcinogenic for humans and for which a MAK value can be derived. ” (Category 5) are sufficient. No MAK values ​​are given for substances in categories 1 and 2, as exposure must be avoided. Before the Hazardous Substances Ordinance came into force, the limit value assigned to them was called the Technical Reference Concentration ( TRK ). MAK values ​​are given for the other categories, but they are provisional and must be observed particularly strictly. For the handling of carcinogenic substances, the TRGS 905 (technical rule for hazardous substances: "List of carcinogenic, mutagenic or reproductive substances") applies.

The same applies to germ cell mutagenic substances (Section IX).

Assessment of the risk in pregnancy

Special conditions apply to pregnant women (Section VIII). For this purpose, the substances of one of the three groups A ("A teratogenic effect has been reliably demonstrated in humans and can also be expected if the MAK and BAT values ​​are complied with.") To C ("A teratogenic effect is required if the MAK and BAT Value not to be feared ”) or D (“ For the assessment of the teratogenic effects either no data are available or the available data are insufficient for a classification into one of the groups A, B or C ”) .

Assessment of the sensitizing effect

Allergenic substances are specifically identified (Section IV), depending on whether the effect affects the skin (“Sh”), the respiratory tract (“Sa”) or the skin and respiratory tract (“Sah”) or whether it is related to photo-contact sensitization (“SP ") leads.

Assessment of the systemic toxicity after skin absorption

Where percutaneous exposure leads to particular stress (Section VII), the "additional designation H" is added.

Mixtures of substances and examples of MAK values

The MAK values ​​apply to individual substances. If several substances are present, only limited conclusions can be drawn from the MAK values ​​as to whether the mixture has a toxic effect. In legal terms, TRGS 402 enables an assessment of the risk in this case. However, TRGS 402 refers to the occupational exposure limit values ​​(AGW) applicable according to the Hazardous Substances Ordinance, not to the recommendations of the MAK commission (MAK values).

Examples of MAK values
Pollutant MAK in mg / m 3 comment
SO 2 2.7
CO 35
CO 2 9100
NO 2 0.95
N 2 O 180
ozone - the earlier MAK value of 0.2 mg / m 3 was suspended
Halothane 41
Enflurane 150
Isoflurane - no MAK value established, as insufficient information
Dust (inhalable) 4th
Dust (respirable) 0.3
bromine - the previous MAK value of 0.1 ml / m 3 was suspended

Connection to other limit value concepts

The maximum immission concentrations - MIK are recommendations for limit values ​​for which air pollution close to the ground in the open air outside the source of emissions for humans, animals or plants is considered to be harmless with permanent exposure . These are determined by the Air Pollution Control Commission , not by the MAK Commission of the DFG. MIK is usually taken as 1/20 of the MAK value:

MIK ~ MAK / 20


In Switzerland, MAK values ​​are issued by Suva in accordance with Art. 50 Paragraph 3 of the Federal Council Ordinance of December 19, 1983 on the Prevention of Accidents and Occupational Diseases. The decree is made in agreement with the limit value commission of the Swiss Association for Occupational Medicine, Industrial Hygiene and Safety at Work ( Suissepro ). The limit values ​​appear in the brochure “Limit values ​​at the workplace”, which is published by Suva.

In Switzerland, MAK values ​​are assigned for carcinogenic substances (additional classification C1 to C3). Compliance with the MAK value does not protect certain genotoxic carcinogenic substances from a low residual risk of cancer.


The concentration of dangerous substances in the air at the workplace is assessed using limit values. In Austria, MAK and TRK values ​​are binding in accordance with the Limit Values Ordinance (GKV) .


See also

Individual evidence

  1. List of MAK and BAT Values ​​2015, July 6, 2015 , page 10
  2. a b TRGS 900 (technical rule for hazardous substances: occupational exposure limit values )
  3. TRGS 903 (technical rule for hazardous substances: biological limit values )
  4. Standing Senate Commission for the testing of harmful substances (German Research Foundation)
  5. Technical Rule for Hazardous Substances 402 Determining and assessing the hazards associated with activities involving hazardous substances: Inhalation exposure, BAUA, accessed on June 29, 2015.
  6. ^ Website of the German Research Foundation , accessed on March 5, 2018.
  7. ^ Information for science of the DFG from February 21, 2018.
  8. a b c Meaning, use and derivation of MAK values ​​(MAK and BAT values ​​list 2015, Section I)
  9. List of MAK values Permanent Senate Commission for the testing of harmful substances from the German Research Foundation
  10. Section VI of the List of MAK and BAT Values ​​2015
  11. Section III of the List of MAK and BAT Values ​​2015
  12. TRGS 905 (Technical Rule for Hazardous Substances: List of Carcinogenic, Mutagenic or Reproductive Substances )
  13. Section IX of the List of MAK and BAT Values ​​2015
  14. Section VIII of the List of MAK and BAT Values ​​2015
  15. Section IV of the List of MAK and BAT Values ​​2015
  16. Section VII of the List of MAK and BAT Values ​​2015
  17. Technical Rule for Hazardous Substances 402 (Determination and assessment of the hazards in activities involving hazardous substances: Inhalation exposure)
  18. MAK documentation for sulfur dioxide , pdf
  19. MAK documentation for nitrogen dioxide , pdf
  20. MAK documentation for ozone , pdf
  21. MAK documentation for halothane , pdf
  22. MAK documentation for enflurane , pdf
  23. MAK documentation for isoflurane , pdf
  24. General dust limit value, addendum 1997 , (pdf)
  25. General dust limit value (A fraction) (granular bio-persistent dusts (GBS)), addendum 2012 , (pdf)
  26. MAK documentation for bromine , pdf
  27. Ordinance on the Prevention of Accidents and Occupational Diseases (Ordinance on Accident Prevention, VUV)
  28. a b Limit values ​​at the workplace: MAK / BAT values ​​(explanations), physical effects, physical stress. (No longer available online.) Archived from the original on July 18, 2019 ; accessed on July 25, 2019 . Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot /
  29. Limit Value Ordinance 2011 - GKV 2011

Web links

Wiktionary: MAK value  - explanations of meanings, word origins, synonyms, translations