Carcinogens

Many types of cancer are examples of irreversible and progressive diseases, and as such exposure to potential cancer-causing agents (carcinogens) warrants the most stringent and reliable control measures. This is particularly the case as at present there is no theoretically acceptable threshold level of exposure to a carcinogen below which there is no risk to human health. However, scientific evidence has shown that whilst a single exposure to a carcinogen is unlikely to be problematic, carcinogens are most dangerous through repeated exposure even at very low levels.

It is very difficult to link eventual cancers to exposure to a particular chemical agent as cancer can take up to 40 years to develop after initial exposure. However, there exists evidence to firmly incriminate a number of chemical species with others under more or less strong suspicion. Several organisations and bodies provide lists of known or 'suspect' carcinogens, which are classified according to level of proof.

Mutagens and Reproductive Toxins

Mutagens, which are in the main part harmful substances, cause heritable genetic changes (mutations). Most mutations are harmful. Mutagens also tend to be carcinogenic and vice versa.

Substances or agents that can cause adverse effects on the reproductive system, are known to impair fertility or to cause developmental toxicity in humans are defined as 'substances toxic to reproduction'. This definition covers a broader range of health effects than the earlier term 'teratogen' which applied only to substances that adversely affected the developing fetus. The toxic effects may include alterations to the reproductive [sexual] organs and/or the endocrine system (which includes the thyroid and adrenal glands). These effects can occur in both men and women.

Working Safely with Carcinogens, Mutagens and Substances Toxic to Reproduction

Guidance on working with carcinogens, mutagens and substances toxic to reproduction can be found in the University Code of Practice and Guidance entitled 'Working Safely with Carcinogens, Mutagens and Substances Toxic to Reproduction' which gives practical advice to enable users to minimise the risk to health from such substances (including suspected carcinogens). It applies not only to science laboratories but to all departments where carcinogenic, mutagenic or reproductive toxins may be used or generated: a prime example being hardwood dust, which is carcinogenic, being generated in a workshop.

The guidance is concerned with the correct matching of the precautions to the risk and therefore should be read in conjunction with the University Hazardous Substances Policy.

Cambridge list of Carcinogens, Mutagens and Substances Toxic to Reproduction in Groups/Categories 1 and 2

The Cambridge List amalgamates classified substances from 5 reputable sources for which there is sufficient evidence to establish the link between exposure and health effects. This list also includes mutagenic substances and substances toxic to reproduction on the same basis. This list is not exhaustive and has not been edited to remove substances which are unlikely to be found in research such as alcoholic beverages.

It should be noted that the biological agents listed in this document relate to Non-Genetically Modified organisms only and are therefore subject to risk assessment under the COSHH regulations and other relevant legislation. Genetically Modified Organisms (GMOs) are subject to risk assessment under the GMO (Contained Use) Regulations, at which point the possible carcinogenic, mutagenic and teratogenic etc possibilities of the GMO must be taken into consideration, and appropriate control measures applied.

• The Cambridge list of Carcinogens, Mutagens and Substances Toxic to Reproduction in Groups/Categories 1 and 2

For further information and advice, please contact a staff member for chemical safety advice, or email safety@admin.cam.ac.uk.