Section 1990.112 - Classification of potential carcinogensThe following criteria for identification, classification and regulation of potential occupational carcinogens will be applied, unless the Secretary considers evidence under the provisions of §§ 1990.143 , 1990.144 and 1990.145 and determines that such evidence warrants an exception to these criteria.
(a)Category I Potential Carcinogens. A substance shall be identified, classified, and regulated as a Category I Potential Carcinogen if, upon scientific evaluation, the Secretary determines that the substance meets the definition of a potential occupational carcinogen in(2) in a single mammalian species in a long-term bioassay where the results are in concordance with some other scientifically evaluated evidence of a potential carcinogenic hazard, or(3) in a single mammalian species in an adequately conducted long-term bioassay, in appropriate circumstances where the Secretary determines the requirement for concordance is not necessary. Evidence of concordance is any of the following: positive results from independent testing in the same or other species, positive results in short-term tests, or induction of tumors at injection or implantation sites.(b)Category II Potential Carcinogens. A substance shall be identified, classified, and regulated as a Category II Potential Carcinogen if, upon scientific evaluation, the Secretary determines that: (1) The substance meets the criteria set forth in § 1990.112(a) , but the evidence is found by the Secretary to be only "suggestive"; or(2) The substance meets the criteria set forth in § 1990.112(a) in a single mammalian species without evidence of concordance.