Thought this might be useful - am trying to find a defined list. I don't want to be a panic merchant, but we come across carcinogens all the time - UV light is a carcinogen and some of the compounds in my burnt toast this morning are carcinogenic but our immune systems usually pick off disfunctional cells. It's when it doesn't that tumours arise. It must be admitted though that we have more contact with carcinogens than ever before in our history (that I know of).
* A carcinogen is a substance that causes cancer (or is believed to cause cancer).
* A carcinogenic material is one that is known to cause cancer.
* The process of forming cancer cells from normal cells or carcinomas is called carcinogenesis.
A known human carcinogen means there is sufficient evidence of a cause and effect relationship between exposure to the material and cancer in humans. Such determination requires evidence from epidemiologic (demographic and statistical), clinical, and/or tissue/cell studies involving humans who were exposed to the substance in question. Obviously, it is unethical to deliberately test potential carcinogens on humans, so "proving" something (in the rigorous scientific sense) to be a carcinogen in humans is a difficult, demanding and lengthy task!
Substances that are reasonably anticipated to be human carcinogens meet any of the following descriptions:
1. There is limited evidence of carcinogenicity from studies in humans. A cause and effect interpretation is credible, but that alternative explanations such as chance, bias, other variables etc. can not be ruled out. Again, science can never prove a hypothesis, only disprove one. Scientific "facts" are established only when a preponderence of the evidence supports a hypothesis and there is 1) no evidence to disprove it and 2) no equally viable (plausible) alternative hypotheses (theories).
2. There is sufficient evidence of carcinogenicity from studies in experimental animals (such as mice or rats), which indicates there is an increased incidence of malignant and/or a combination of malignant and benign tumors (1) in multiple species or at multiple tissue sites, or (2) by multiple routes of exposure, or (3) to an unusual degree with regard to incidence, site, or type of tumor, or age at onset.
3. There is less than sufficient evidence of carcinogenicity in humans or laboratory animals; however, the substance is structurally related to other materials that are either human carcinogens or reasonably anticipated to be human carcinogens.
4. There is convincing relevant information that the material acts through mechanisms that are likely to cause cancer in humans.
A wide variety of information is required to assess carcinogenicity and risks to humans. For example, a substance may cause cancer in laboratory animals, but the mechanism by which this occurs may not occur in humans.