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Working with carcinogens and reprotoxic agents (GHS)

Based upon the labelling according the Globally Harmonized System (GHS).

For more information about the rules about labelling see: Labelling hazardous substances (WMS or GHS).


Substances which can cause or promote cancer in humans are considered to be carcinogenic. This can take place by means of exposure to a single (carcinogenic) agent or a (carcinogenic) mixture. Mutagenic agent scan alter a cell’s genetic material (mutate).

Certain substances do not threaten the health of the employees themselves, but the possibility to produce offspring or the health of this offspring. These substances are referred to as reprotoxic and often classified as follows:

  • Effects on the reproductive organs (for example damage to the hormonal regulation);
  • Effects on reproductive cells (sperm and/or egg-cells) by mutations in the DNA or damage to the chromosomes;
  • Effects on the unborn baby in the womb. These agents are also referred to as feto-toxic;
  • Effects on the baby through breast milk.


Carcinogenic, mutagenic and reprotoxic agents are recognisable by the danger symbol and the hazard statements:

  • H340: May cause genetic defects;
  • H350: May cause cancer;
  • H360: May damage fertility or the unborn child.

In addition, there are agents which are suspect. These agents are recognisable by the same danger symbol but other hazard statements:

  • H341: Suspected of causing genetic defects;
  • H351: Suspected of causing cancer;
  • H361: Suspected of damaging fertility or the unborn child.

If it is certain or likely that an employee will perform activities involving carcinogens or reprotoxic agents, the guidelines – as described in this document – have to be followed. The influence of any work-related damaging factors on the fertility and genetic material of both men and women is relevant before any pregnancy. The regulation on reprotoxic agents therefore applies not only during the pregnancy or the period of breast-feeding, but also in particular in the preceding period for persons (male/female) with a desire to have children.


Activities involving carcinogenic or reprotoxic agents may only be carried out under certain preconditions. These conditions are laid down in both the environmental and working conditions legislation.

The Working Conditions Decree states in articles 4.2 and 4.13 that within the context of the risk identification and assessment at each workplace the possible exposure to carcinogenic and reprotoxic substances is to assessed and, if necessary, measured in order to determine where and to what extent staff members may be exposed to hazardous substances.

In addition to the general obligation to register hazardous substances (see working with hazourdous substances) there is an additional obligation to register carcinogenic and reprotoxic substances (see under Performing a risk identification and assessment).

A large organisation that employs a lot of women will always have a number of pregnant and breastfeeding women among them. Employers are to have a policy in place on pregnancy. An employer should organise the work performed by a pregnant or breastfeeding women in such a way that it does not pose any danger to her own safety and that of the (unborn) child. See for this the UT-scheme Working during pregnancy and breastfeeding.


Within the UT most of the carcinogenic and reprotoxic substances are found at the technical faculties. These substances are used for research or – to a limited extent – educational purposes. Since knowledge and expertise relating to these substances is concentrated with the staff members involved in this research, the responsibility to observe the rules and regulations lies in particular with the supervisors and users of these substances.


A risk identification should be aimed at the nature, extent and length of the staff member’s exposure to (suspect) carcinogenic/reprotoxic substances. The following is to be taken into account:

I The identity of the substance or mixture

  • Carcinogenic/reprotoxic substance 
    record the chemical name and the Einecs-number (possibly CAS-number) and any limiting values of the substance (MAC) and information on the existence of a ‘safe value' .
  • Carcinogenic/reprotoxic mixture or preparation
    record the trade name(s), the chemical name of these carcinogenic component(s) and the weight percentages of these carcinogenic component(s).

II The nature and dangers of the substance(s) the substances used are in solid, liquid or gaseous state

  • regarding solid substances: possible quick diffusion of powders or crystals;
  • regarding liquids: if there is a risk of splashing, a vapour may quickly form;
  • regarding gases: weight of the gas (in relation to air), possible formation of haze.

III Motivation for the required use of the substance or process, as well as an explanation why replacement of the substance(s) is not possible. It is important that reasons are stated as to why replacing the carcinogenic/reprotoxic substance is not possible (no alternative available).

IV The department where the substances are found or the process takes place (name, number of the space(s) where the substance(s) is (are) used and stored).

V The amount of the substance available each year for use by staff members and the frequency of application of the process.

VI The nature of the activities performed:

  • is the substance handled manually, mechanically or in an automated way?
  • is there an open or closed system?

VII The way in which the exposure may take place. This concerns exposure that would exist if no precautionary measures were taken (so-called potential exposure).

  • examine whether exposure may take place as a result of inhalation of vapour (aerosol) or via the skin or mouth;
  • take into account any reinforcing effects that may arise when exposed to several substances (for example in combination with a solvent, easy penetration via skin);
  • identify the calamities that may occur at the various steps during the process.

VIII On the basis of the risk identification of the above point (groups of) staff members may be identified who may come into contact with the substances. For example: scientific staff, students and technicians. The names of these staff members should be recorded.

IX Plan of action

Indicate what measures are taken to prevent exposure.

  • As control at the source is reasonably unfeasible: ventilation, separation of person and source or in extreme cases, using personal protective gear to protect against residual risks.
  • What needs to be done to prevent calamities (identified in step VII).



Activities involving carcinogenic and reprotoxic substances should take place in a separate work space or in a separate workplace that is separate from the work space and workplaces where it is not permitted to work with carcinogenic or reprotoxic substances. This separate space should be clearly marked by warning signs (for example: “prohibited space for unauthorised persons”). Persons not working in these spaces should be barred from these spaces as much as possible. Eating and drinking in these spaces is of course not permitted.


Packaging containing carcinogenic or reprotoxic substances should always be recognisable as such. The label on the packaging must provide the following information:

  • Chemical name of the hazardous substances;
  • Danger symbols (see chapter 1);
  • H-sentences and P-sentences.

This means that also bottles, erlenmeyer flasks and suchlike are to be provided with such labels if the content after production or pouring over is stored (for longer than one day). For one-day work solutions it will suffice to state the chemical name of the hazardous components.

The storage of these substances has to be in accordance with the UT’s environmental permit (in accordance with PGS 15 guidelines or equivalent). See for this the UT guideline Storage of hazardous substances.

At the UT we have detailed rules relating to the collection of waste and the removal of hazardous substances, see: Waste management regulation University of Twente.


With the assistance of the in-house emergency service it should be examined whether a special calamities procedure is to be put in place. If so, this is to be included in the information to the relevant staff and in-house emergency service staff.


If exposure to carcinogenic substances is possible and this can also result in (discernable) health risks, it is necessary to have the staff member undergo an occupational health examination (AGO). The examination should at any rate take place the first time that the activities with the carcinogenic substances are performed. Staff members working with carcinogenic substances can state at any time that they wish to undergo a follow-up examination.

Precisely how the examination is conducted depends entirely on the substance used. This is to be consulted with the working conditions service (where the examination is to be conducted). For example, measuring the substance in the blood or urine or exhalation air. Points of attention for carrying out the AGO are:

  • The working conditions service should be aware of the conditions and circumstances of the exposure;
  • A medical file is to be drawn up in which also the occupational history of the relevant staff member is to be recorded;
  • The working conditions service should have a personal interview with the staff member;
  • If considered necessary (useful), measurements of blood, urine and exhalation air can be carried out.


Staff members are to be informed of the risks they run by working with hazardous substances. The following should be made clear to the staff member:

  • the possible health hazards as a result of exposure to the substances and vapours which the staff member handles;
  • special attention is required for women and men in the reproductive age when they start working with substances that are hazardous to reproduction; if the substances present are hazardous to the unborn child women in the reproductive age should be informed of this immediately;
  • the existing rules, the content and the significance of a medical (health) examination to be repeated periodically;
  • the rules and regulations regarding the carcinogenic/reprotoxic substances;
  • the safety and precautionary measures and the reasons why these have been taken;
  • the protective gear made available and the way in which these are to be used and maintainedt.


When working with hazardous substances it is obligatory to wear safety goggles and a laboratory coat. Depending on the nature of the activities (see under Performing a risk identification and assessment) other protective gear is to be worn as well. For this see also the personnal protective-equipment (guideline working with personal protective gear).


  1. Arbo-informatieblad, number 6: kankerverwekkende stoffen en processen(carcinogenic substances and processes) (publishers SDU)
  2. Arbo-informatieblad, number 12: arbeid en zwangerschap (work and pregnancy) (publishers SDU)
  3. Arbobesluit (Working conditions decree), Chapter 4
  4. Arbo-themacahier, number 5: risicogroepen op de werkplek (risk groups at the workplace) (publishers SDU)

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