User Guide to Thresholds and Classification - Environmental ...

222User Guide for Thresholds and Classifications15.2. Carcinogenicity threshold and classification criteria15.2.1. Carcinogenicity threshold criteriaSchedule 4 to the Hazardous Substances (Minimum Degrees of Hazard) Regulations 2001 states:2 Minimum degrees of hazard(1) A substance with toxic properties is not hazardous for the purposes of the Act unless—…(p) reliable information for the substance indicates to an expert that exposure to thesubstance causes the development of cancer or an increase in the incidence of benign ormalignant tumours in an organ or an organism.15.2.2. Carcinogenicity classification criteriaSchedule 4 to the Hazardous Substances (Classification) Regulations 2001 identifies two classificationcategories for substances that are carcinogenic (subclass 6.7).Category 6.7A – substances that are known or presumed human carcinogensa. A substance for which data indicate sufficient evidence in humans of a causal relationship betweenexposure to the substance and the development of cancer in humans.b. A substance for which data indicate sufficient evidence in animals of a causal relationship betweenexposure to the substance and an increased incidence of tumours.c. A substance for which data indicate:i. limited evidence in humans of a positive correlation between exposure to the substance and thedevelopment of human cancer; andii. limited evidence in animals that exposure to the substance may lead to an increased incidence oftumours.Category 6.7B – substances that are suspected human carcinogens:A substance for which data indicate limited evidence in humans or limited evidence in animals thatexposure to the substance may lead to the development of cancer or an increased incidence of tumours,where the strength and weight of the evidence indicate to an expert that the evidence is not sufficient toclassify the substance in hazard classification 6.7A.The classification criteria above are based on the Globally Harmonised System for Classification andLabelling of Chemicals (GHS) (United Nations, 2007). See Appendix 15B for a comparison of the HSNO Actcriteria with those of the GHS. See Appendix 15C for comparisons with the EU and other jurisdictions‘ criteriafor carcinogenicity.‗Evidence‘ in carcinogenicity studies involves the enumeration of tumours in human and animal studies anddetermination of their level of statistical significance. Sufficient human evidence demonstrates causalitybetween human exposure and the development of cancer, whereas sufficient evidence in animals shows acausal relationship between the agent and an increased incidence of tumours. Limited evidence in humansJanuary 2012 EPA0109