What are Carcinogens and Mutagens?

A carcinogen means

(a) a substance or mixture which meets the criteria for classification as a category 1A or 1B carcinogen set out in Annex I to Regulation (EC) No. 1272/2008 of the European Parliament and of the Council (CLP Regulations)

(b) a substance, mixture or process referred to in Annex I to the Directive (CMD as amended) as well as a substance or mixture released by a process referred to in that Annex  (CMD Annex 1 consolidated)

What is a Mutagen?

A mutagen means

  • a substance or mixture which meets the criteria for classification as a category 1A or 1B germ cell mutagen set out in Annex I to Regulation (EC) No. 1272/2008 (CLP).

How are Carcinogens and Mutagens classified?

Carcinogenic and mutagenic substances are classified into a number of categories under the CLP Regulations: 

  • A category 1A (Carc1A) carcinogen is a substance known to have carcinogenic potential for humans, classification is largely based on human evidence.
  • A category 1B (Carc1B) is a substance which is presumed to have carcinogenic potential for humans, classification is largely based on animal evidence.
  • A category 1A mutagen (Muta1A) is a substance known to induce heritable genetic mutations or to be regarded as if they induce heritable mutations in the germ cells of humans. The classification is based on positive evidence from human epidemiological studies.
  • A category 1B mutagen (Muta1B) is a substance known to induce heritable genetic mutations or to be regarded as if they induce heritable mutations in the germ cells of humans. The classification is based on positive mutagenicity test results on cells in humans.

How do I know if the substance or mixture is a ‘carcinogen’ or "mutagen"?

  • Check the label and safety data sheet (SDS) for the substance or mixture to determine whether or not the material is carcinogenic or mutagenic.  Look out for the following:

 Classification          Code        Hazard Statement

  • Carc 1A, 1B     H350       May cause cancer

  • Carc 1A, 1B     H350i      May cause cancer by inhalation

  • Muta 1A, 1B    H340       May cause genetic defects

    Are there any other categories?

    A third category of carcinogen/mutagen exists and while these fall outside the specific scope of the carcinogen regulations they must still be  risk assessed under the Chemical Agents Regulations and the Safety. Health and Welfare at Work Act, 2005

    • Category 2 carcinogens are suspected human carcinogens. This is based on evidence obtained from human and/or animal studies but which is not sufficient for a Category 1 classification
    • Category 2 mutagens cause concern for human owing to the possibility that they may induce heritable mutations in the germ cells of humans.

    Category 2 substances and mixtures will be labelled:

    • Classification    Code        Hazard Statement
    • Carc 2              H351       Suspected of causing cancer
    • Muta 2             H341       Suspected of causing genetic defects.