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Publication of Results of Investigations and Recommendations for a Substance - 1,1,2,2-Tetrachloroethane (Subsections 68(b) and (c) of the Canadian Environmental Protection Act, 1999) Whereas two summaries of a follow-up report to the assessment of 1,1,2,2-Tetrachloroethane, a substance originally specified on the first Priority Substances List, are annexed hereby, Notice therefore is hereby given that the Ministers of the Environment and of Health propose to take no further action at this time in respect of the said substance. Public Comment Period Any person may, within 60 days of publication of this notice, file with the Minister of the Environment, comments with respect to this proposal. All comments must cite the Canada Gazette, Part I, and the date of publication of this notice and be sent to the Director, Existing Substances Branch, Department of the Environment, Hull, Quebec K1A 0H3, (819) 953-4936 (Facsimile), or by electronic mail to PSL.LSIP@ec.gc.ca. The comments should stipulate those parts thereof that should not be disclosed pursuant to the Access to Information Act and, in particular, pursuant to sections 19 and 20 of that Act, the reason why those parts should not be disclosed and the period during which they should remain undisclosed. JOHN ARSENEAU Director General Toxic Pollution Prevention Directorate On behalf of the Minister of the Environment ROD RAPHAEL Director General Safe Environments Programme On behalf of the Minister of Health Annex Summary of the Follow-up Report to the Environmental Assessment of the substance 1,1,2,2-Tetrachloroethane 1,1,2,2-Tetrachloroethane, which appeared on the first Priority Substances List (PSL1), was assessed to determine whether it should be considered "toxic" as defined under the Canadian Environmental Protection Act (CEPA). It was concluded that 1,1,2,2-tetrachloroethane was not "toxic" under paragraph 11(b) of CEPA; however, there was insufficient information to conclude whether 1,1,2,2-tetrachloroethane constituted a danger to the environment under paragraph 11(a). Information was lacking about the potential effects of the substance on terrestrial biota. No information is available concerning the effects of 1,1,2,2-tetrachloroethane on wildlife. Based on currently available toxicity studies conducted on laboratory animals, it is unlikely that wildlife would be adversely affected by the concentrations of 1,1,2,2-tetrachloroethane reported in the Canadian environment. No information was identified on the potential effects of 1,1,2,2-tetrachloroethane on plants exposed through the atmosphere. Based on toxicity information available for several PSL1 substances that are structurally similar to 1,1,2,2-tetrachloroethane, it is concluded that terrestrial plants are unlikely to be adversely affected by the concentrations of the substance reported in the Canadian atmosphere. Based on the information currently available, it is proposed that 1,1,2,2-tetrachloroethane is not entering the environment in a quantity or concentration or under conditions that have or may have an immediate or long-term harmful effect on the environment or its biological diversity. Therefore, it is proposed that 1,1,2,2-tetrachloroethane not be considered "toxic" as defined in paragraph 64(a) of the Canadian Environmental Protection Act, 1999. The results of the U.S. National Toxicology Program (NTP) study will be evaluated when they become available, as they could affect the assessment of potential effects of 1,1,2,2-tetrachloroethane on wildlife. The full Follow-up Report may be obtained from the Existing Substances Evaluation, First Priority Substances List Report Page (http://www.ec.gc.ca/substances/ese/eng/PSAP/PSL1_IIC.cfm) or from the Inquiry Centre, Environment Canada, Hull, Quebec K1A 0H3 (1-800-668-6767). Summary of the Follow-up Report to the Human Health Assessment of the substance 1,1,2,2-Tetrachloroethane 1,1,2,2-Tetrachloroethane is not produced in nor imported into Canada, although it is released to the Canadian environment primarily in emissions to ambient air during production of other chemicals and from waste disposal sites; it also enters the Canadian environment as a result of long-range atmospheric transport from other countries. Information concerning the presence of 1,1,2,2-tetrachloroethane in products imported into Canada has not been identified. 1,1,2,2-Tetrachloroethane was included on the first Priority Substances List (PSL1) under the 1988 Canadian Environmental Protection Act (CEPA 1988) for assessment of potential risks to the environment and human health. As outlined in the Assessment Report released in 1993, relevant data identified before September 1992 were considered insufficient to conclude whether 1,1,2,2-tetrachloroethane was "toxic" to human health as defined in paragraph 11(c) under CEPA 1988. Additional monitoring data were identified during the period following the release of the PSL1 Assessment Report (prior to December 2000), and estimates of exposure were accordingly updated. Additional critical toxicological data in experimental species or humans relevant to assessment of the human health risks for 1,1,2,2-tetrachloroethane have not been identified, although an important 13-week study conducted by the U.S. National Toxicology Program (NTP) is nearing completion. The available data provide some evidence that 1,1,2,2-tetrachloroethane may be carcinogenic in humans, although information is inadequate as a basis for classification in Group II ("probably carcinogenic to humans"). Based on the limited available information, the margin of exposure between concentrations in the principal media of exposure (ambient and indoor air) for the general public and observed effect levels is considered sufficient to protect human health. Based on available data, it is concluded, therefore, that 1,1,2,2-tetrachloroethane is not entering the environment in a quantity or concentration or under conditions that may constitute a danger to human life or health. Therefore, the Ministers of the Environment and of Health propose that 1,1,2,2-tetrachloroethane not be considered "toxic" to human health as defined in paragraph 64(c) of the Canadian Environmental Protection Act, 1999. It is recommended that uses and emissions of this compound continue to be monitored to ensure that exposure does not increase to any significant extent and that the potential impact, if any, on the outcome of this assessment be considered when the final report of the NTP subchronic study is available. The full Follow-up Report may be obtained from the Existing Substances Evaluation, First Priority Substances List Report Page (http://www.ec.gc.ca/substances/ese/eng/PSAP/PSL1_IIC.cfm) or from the Inquiry Centre, Environment Canada, Hull, Quebec K1A 0H3 (1-800-668-6767). [39-1-o]
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