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Exposure to carcinogens, mutagens or reprotoxic substances at work



Directive 2004/37/EC – protection from the risks related to exposure to carcinogens or mutagens at work


  • The directive sets out European Union (EU) rules on the minimum requirements for protecting workers against risks to their health and safety arising, or likely to arise, from exposure to carcinogens*, mutagens* or reprotoxic substances* (CMRs) at work, including the prevention of such risks.
  • It lays down particular minimum requirements and limit values in this area.
  • It has been amended several times, most recently in 2022 by Directive (EU) 2022/431, which brought reprotoxic substances under the scope of the directive and added or amended exposure limit values for certain carcinogens and mutagens.



  • The directive applies to a substance or mixture which meets the criteria for classification as a category 1A or 1B carcinogen, a category 1A or 1B germ cell mutagen or a category 1A or 1B reproductive toxicant set out in Annex I to Regulation (EC) No 1272/2008 (see summary).
  • In addition, it applies to a substance, mixture or process referred to in Annex I to the directive, along with substances or mixtures released by processes referred to in that annex:
    • manufacture of auramine;
    • work involving exposure to polycyclic aromatic hydrocarbons present in coal soot, coal tar or coal pitch;
    • work involving exposure to dusts, fumes and sprays produced during the roasting and electro-refining of cupro-nickel mattes;
    • strong acid process in the manufacture of isopropyl alcohol;
    • work involving exposure to hardwood dusts;
    • work that generates respirable crystalline silica dust;
    • work involving dermal exposure to mineral oils that have been used before in internal combustion engines to lubricate and cool the moving parts within the engine;
    • work involving exposure to diesel engine exhaust emissions.
  • It does not apply to workers exposed only to radiation covered by the Treaty establishing the European Atomic Energy Community.
  • It applies to workers exposed to asbestos when its rules are more favourable to health and safety at work than those of Directive 2009/148/EC (see summary).
  • Directive 89/391/EEC (see summary) applies in full, without prejudice to more stringent and/or specific rules contained in Directive 2004/37/EC.

Determining exposure and assessing risks

  • For any activity likely to involve a risk of exposure to CMRs, the nature, degree and duration of workers’ exposure must be determined on a regular basis to assess any risk to their health or safety and to lay down the measures to be taken. All routes of exposure must be taken into account, including absorption into and/or through the skin.
  • Attention must be paid to workers who are at particular risk and employers should consider not employing them in areas where they may come into contact with CMRs.
  • Employers must supply the authorities with the information used for making the risk assessment when requested.

Employers’ obligations

  • Reduction and replacement. Employers must reduce the use of CMRs at the place of work, in particular by replacing them, if technically possible, by a substance, mixture or process that under its conditions of use is not dangerous or is less dangerous to workers’ health or safety.
  • Prevention and reduction of exposure. When the risk assessment reveals a risk to workers’ health or safety, workers’ exposure must be prevented.When it is not technically possible to replace the CMR by a substance which is not dangerous or is less dangerous, the employer must ensure that the CMR is, if technically possible, manufactured and used in a closed system. If this is not technically possible, employers must ensure that the level of exposure to the CMR is as low as is technically possible.
  • Where it is not possible to use or manufacture a threshold reprotoxic substance in a closed system, the employer must ensure that the risk related to the exposure of workers to that substance is reduced to a minimum. This also applies to reprotoxic substances other than non-threshold reprotoxic substances and threshold reprotoxic substances, for which the employer, when carrying out the risk assessment, must consider the possibility that there is no safe level of exposure for workers’ health and shall lay down appropriate measures in that regard.
  • Exposure to CMRs must not exceed the limit values set out in Annex III.
  • Whenever CMRs are used, the directive lists a series of measures all of which the employer must apply (limiting the quantities used, limiting the number of workers exposed, design of work processes, etc.).

Information for the responsible authority

  • Where the results of the risk assessment reveal a risk to workers’ health or safety, the employer must, when requested by the responsible authorities, make information available to those authorities on:
    • the numbers of workers exposed;
    • the preventive measures taken; and
    • the activities and/or industrial processes carried out, including the reasons why CMRs are being used.

Unforeseeable exposure

  • Where unforeseeable incidents or accidents are likely to lead to workers being abnormally exposed, employers must inform their workers accordingly.
  • Until the situation has been restored to normal by eliminating the causes of the abnormal exposure, only those workers who are essential to the carrying out of repairs and other necessary work shall be permitted to work in the affected area. In these situations:
    • protective clothing and respiratory personal protective equipment must be worn;
    • the exposure may not be permanent and shall be kept to the strict minimum of time necessary for each worker; and
    • unprotected workers shall not be allowed to work in the affected area.

Foreseeable exposure

  • Where there is a foreseeable risk of significant increase of exposure, for example during maintenance work, and once all other technical preventive measures for limiting workers’ exposure have been taken, employers must reduce the duration of workers’ exposure to a strict minimum and ensure their protection by providing the necessary protective clothing and individual respiratory protective equipment, which the workers must wear as long as the abnormal exposure persists. The exposure may not be permanent and shall be kept to the strict minimum of time necessary for each worker.
  • All areas used for such activities must be clearly demarcated and indicated and unauthorised persons must be prevented by other means from having access to such areas.

Access to risk areas

  • Employers must restrict access to risk areas to those workers who have to enter such areas because of their work or duties.

Hygiene and personal protection

  • Employers must take the following measures for all activities that carry a risk of contamination by CMR:
    • ensure that workers do not eat, drink or smoke in work areas where there is a risk of CMR contamination;
    • supply workers with the appropriate protective or other appropriate special clothing;
    • provide separate storage places for work or protective clothes and street clothes;
    • provide washing and toilet facilities;
    • properly store, check and clean protective equipment, if possible before and in any case after every use;
    • ensure that any defective equipment is repaired or replaced before further use.
  • Workers must not bear the cost of these measures.

Informing, training and consulting workers

Employers must ensure that:

  • workers and/or their representatives receive, on the basis of all available information, in particular in the form of information and instructions, sufficient and suitable training about:
    • potential and additional health risks (including smoking),
    • precautions for preventing exposure,
    • hygiene requirements,
    • protective equipment and clothing,
    • steps to be taken by workers, including rescue workers, in the event of an incident and to prevent incidents;
  • the training is adapted to take account of any new or changed risk when workers are exposed or are likely to be exposed to new CMRs or to a number of different CMRs, including those contained in hazardous medicinal products, or in case of changing circumstances related to work;
  • trainings are provided periodically in healthcare settings to all workers who are exposed to CMRs, in particular where new hazardous medicinal products containing those substances are used, and are repeated periodically in other settings if necessary.

Employers shall inform workers of installations and related containers containing CMRs and ensure that all containers, packages and installations containing CMRs are clearly and legibly labelled and that warning signs are clearly displayed.

Where a biological limit value* has been set in Annex IIIa, health surveillance is mandatory for working with the CMR in question, in line with the procedures in that annex. Workers shall be informed of that requirement before being assigned to the task involving the risk of exposure to this CMR.

Measures must be taken to ensure that workers and/or any workers’ representatives:

  • are able to check whether the directive is being applied or can be involved in its application, in particular with regard to the consequences for workers’ safety and health of the selection, wearing and use of protective clothing and equipment, and the measures determined by the employer regarding foreseeable exposure, without prejudice to the employer’s responsibility for determining the effectiveness of protective clothing and equipment and such measures regarding foreseeable exposure;
  • are informed as soon as possible in the event of abnormal exposure of the causes thereof and of the measures taken or to be taken to rectify the situation.

Measures must be taken to ensure that:

  • employers keep an updated list of workers undertaking activities that carry a risk to their health and safety, indicating, if the information is available, the exposure to which they have been subjected;
  • the doctor and/or the responsible authority as well as all other persons who have responsibility for health and safety at work have access to the above list;
  • each worker has access to the information on the list which relates to them personally;
  • workers and/or any workers’ representatives have access to anonymous collective information;
  • workers and/or their representatives are consulted about and involved in all matters related to CMR exposure, in accordance with Directive 89/391/EEC.

Miscellaneous measures

Health surveillance

  • EU Member States must establish arrangements for monitoring workers’ health and safety, in accordance with national law or practice, so that, if appropriate, their health is adequately monitored prior to exposure and at regular intervals afterwards for as long as deemed necessary to safeguard health. The doctor or authority responsible for the health surveillance of workers may indicate that health surveillance must continue after the end of exposure, for as long as they consider it to be necessary to safeguard the health of the worker concerned.
  • These health surveillance arrangements must make it possible to directly apply individual and occupational hygiene measures. When a worker’s health is monitored, an individual medical file is to be created. The doctor or authority must propose any protective or preventive measures to be taken in respect of any individual workers.
  • Information and advice must be given to workers regarding any health surveillance which they may undergo following the end of exposure.
  • If a worker is found to be suffering from an abnormality which is suspected to be the result of exposure to CMRs, or if a biological limit value is found to have been exceeded, the doctor or authority responsible for the health surveillance of workers may require other workers who have been similarly exposed to undergo health surveillance.
  • There are practical recommendations on the monitoring of workers’ health in Annex II.
  • All cases of cancer, adverse effects on sexual function and fertility in adult male and female workers or developmental toxicity in their offspring identified in accordance with national law or practice as resulting from occupational exposure to a CMR substance must be notified to the responsible authority. Member States must take this information into account in their reports submitted to the European Commission under Directive 89/391/EEC.


  • For carcinogens and mutagens, the up-to-date list of workers who have been exposed which the employer is required to keep and individual medical files must be kept for at least 40 years after the end of exposure.
  • For reprotoxic substances, the up-to-date list of workers undertaking activities that carry a risk to their health and safety in terms of exposure and the medical record must be kept for at least 5 years following the end of exposure.
  • These documents must be made available to the responsible authority in cases where the undertaking ceases activity.


  • The directive had to be transposed into national law by 31 December 1992. Its rules should apply from 20 May 2004.
  • Amending Directive (EU) 2022/431 has to be transposed into national law by 5 April 2024.


For further information, see:

Directive 2004/37/EC codifies and replaces Directive 90/394/EEC and its successive amendments, Directives 97/42/EC and 1999/38/EC.


Carcinogens. Substances with the potential to cause cancer in an organism.
Mutagens. Substances that change the genetic material of an organism.
Reprotoxic substances. Substances that interfere with reproduction (for example, infertility, miscarriages and foetal malformations). In the directive, a distinction is made between those for which an exposure threshold can be defined, below which there are no harmful effects on workers’ health (threshold reprotoxic substance), and those for which there is no safe level of exposure for workers’ health (non-threshold reprotoxic substance). Both are identified as such in the notation column of Annex III to the directive.
Biological limit value. Limit of the concentration in the appropriate biological medium of the relevant agent, its metabolite or an indicator of effect.


Directive 2004/37/EC of the European Parliament and of the Council of 29 April 2004 on the protection of workers from the risks related to exposure to carcinogens or mutagens at work (Sixth individual Directive within the meaning of Article 16(1) of Council Directive 89/391/EEC) (codified version) (OJ L 158, 30.4.2004, pp. 50–76). Text published in corrigendum (OJ L 229, 29.6.2004, pp. 23–34).

Successive amendments to Directive 2004/37/EC have been incorporated in the original text. This consolidated version is of documentary value only.


Directive 2009/148/EC of the European Parliament and of the Council of 30 November 2009 on the protection of workers from the risks related to exposure to asbestos at work (OJ L 330, 16.12.2009, pp. 28–36).

See consolidated version.

Regulation (EC) No 1272/2008 of the European Parliament and of the Council of 16 December 2008 on classification, labelling and packaging of substances and mixtures, amending and repealing Directives 67/548/EEC and 1999/45/EC, and amending Regulation (EC) No 1907/2006 (OJ L 353, 31.12.2008, pp. 1–1355).

See consolidated version.

Council Directive 89/391/EEC of 12 June 1989 on the introduction of measures to encourage improvements in the safety and health of workers at work (OJ L 183, 29.6.1989, pp. 1–8).

See consolidated version.

last update 01.06.2022