Priority Substances List - Statement of the Science Report for Ethylene Oxide

1.0 Introduction

The Canadian Environmental Protection Act, 1999 (CEPA 1999) requires the federal Ministers of the Environment and of Health to prepare and publish a Priority Substances List (PSL) that identifies substances, including chemicals, groups of chemicals, effluents and wastes, that may be harmful to the environment or constitute a danger to human health. The Act also requires both Ministers to assess these substances and determine whether they are "toxic" or are capable of becoming "toxic" as defined in Section 64 of the Act, which states:

...a substance is toxic if it is entering or may enter the environment in a quantity or concentration or under conditions that

1. have or may have an immediate or long-term harmful effect on the environment or its biological diversity;
2. constitute or may constitute a danger to the environment on which life depends; or
3. constitute or may constitute a danger in Canada to human life or health.

Substances that are assessed as "toxic" as defined in Section 64 may be placed on Schedule I of the Act and considered for possible risk management measures, such as regulations, guidelines, pollution prevention plans or codes of practice to control any aspect of their life cycle, from the research and development stage through manufacture, use, storage, transport and ultimate disposal.

Based on initial screening of readily accessible information, the rationale for assessing ethylene oxide provided by the Ministers' Expert Advisory Panel on the Second Priority Substances List (Ministers' Expert Advisory Panel, 1995) was as follows:

Large volumes of ethylene oxide are used to produce ethylene glycol. Ethylene oxide is present in fossil fuel emissions and tobacco smoke. It is released in gaseous and liquid forms during its production, and from its use in manufacturing other compounds. Ethylene oxide is a human carcinogen and is mutagenic to animals. It was determined that an assessment is necessary to characterize the extent of exposure and the associated risk to human health and the Canadian environment.

Descriptions of the approaches to assessment of the effects of Priority Substances on the environment and human health are available in published companion documents. The document entitled "Environmental Assessments of Priority Substances under the Canadian Environmental Protection Act. Guidance Manual Version 1.0 - March 1997" (Environment Canada, 1997a) provides guidance for conducting environmental assessments of Priority Substances in Canada. This document may be purchased from:

• Environmental Protection Publications
  Environmental Technology Advancement Directorate
  Environment Canada
  Ottawa, Ontario
  KIA 0H3

It is also available on the Commercial Chemicals Evaluation Branch web site at www.ec.gc.ca/cceb1/ese/eng/esehome.htm under the heading "Guidance Manual." It should be noted that the approach outlined therein has evolved to incorporate recent developments in risk assessment methodology, which will be addressed in future releases of the guidance manual for environmental assessments of Priority Substances.

The approach to assessment of effects on human health is outlined in the following publication of the Environmental Health Directorate of Health Canada: "Canadian Environmental Protection Act - Human Health Risk Assessment for Priority Substances" (Health Canada, 1994), copies of which are available from:

• Environmental Health Centre
  Room 104
  Health Canada
  Tunney's Pasture
  Ottawa, Ontario
  K1A 0L2

or on the Environmental Health Directorate publications web site (www.hc-sc.gc.ca/ehp/ehd/catalogue/bch.htm). The approach is also described in an article published in the Journal of Environmental Science and Health - Environmental Carcinogenesis & Ecotoxicology Reviews (Meek et al., 1994). It should be noted that the approach outlined therein has evolved to incorporate recent developments in risk assessment methodology, which are described on the Environmental Substances Division web site (www.hc-sc.gc.ca/ehp/ehd/bch/env_contaminants/psap/psap.htm) and which will be addressed in future releases of the approach paper for the assessment of effects on human health.

The search strategies employed in the identification of data relevant to assessment of potential effects on the environment (prior to May 1998) and human health (prior to January 1999) are presented in Appendix A. Review articles were consulted where appropriate. However, all original studies that form the basis for determining whether ethylene oxide is "toxic" under CEPA 1999 have been critically evaluated by staff of Environment Canada (entry and environmental exposure and effects) and Health Canada (human exposure and effects on human health).

Sections of this Assessment Report and supporting documentation (Environment Canada, 1999) related to the environmental assessment of ethylene oxide were prepared by M. Lewis of Environment Canada. An initial draft of the environmental assessment was prepared by D. Moore and S. Teed of Cadmus Group Inc. on behalf of Environment Canada. Other members of the Environmental Resource Group who reviewed the documents and participated in discussions were:

• M. Alaee, Environment Canada
• Y. Bovet, Environment Canada
• N. Bunce, University of Guelph
• L. Hamel, Union Carbide Canada Inc.
• R. Kent, Environment Canada
• G. Parsons, Huntsman Corp.
• J. Prinsen, Environment Canada
• R. Romano, Chemical Manufacturers Association
• S. Smythe-Plewes, Ontario Hospital Association

The environmental sections of the Assessment Report and supporting documentation (Environment Canada, 1999) were also reviewed by internal reviewers at Environment Canada -namely, K. Lloyd and P. Doyle - as well as by external reviewers: D. Maletski (BUA, Germany) and D. Markwordt (U.S. Environmental Protection Agency).

The health-related sections of this Assessment Report and supporting documentation were prepared by the following staff of Health Canada:

• R. Beauchamp
• M. Berci
• W. Bruce
• R.G. Liteplo
• M.E. Meek
• D. Moir
• M. Walker
  
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Sections of the Assessment Report and supporting documentation on genotoxicity were reviewed by G. Douglas (Environmental and Occupational Toxicology Division, Health Canada). In order to address primarily adequacy of coverage, sections of the supporting documentation pertaining to human health were reviewed externally by:

• T. Fennel, Chemical Industry Institute of Toxicology
• R. Gingell, Shell Chemical Co.
• L. Recio, Chemical Industry Institute of Toxicology
• W.M. Snellings, Union Carbide
• M.J. Teta, Union Carbide
• Walker, New York State Department of Health

Accuracy of reporting, adequacy of coverage and defensibility of conclusions with respect to hazard characterization and dose-response analysis were considered in written review by staff of the Information Department of BIBRA International and at a panel meeting of the following members, convened by Toxicology Excellence for Risk Assessment (TERA) on August 12, 1999, in Ottawa, Canada:

• M. Bogdanffy, DuPont Haskel Laboratory
• J. Christopher, California Environmental Protection Agency
• M. Dourson, TERA
• S. Felter, Procter & Gamble
• J. Mandel, Exponent
• R. Rudel, Silent Spring Institute
• V. Walker, New York State Department of Health

J. Preston (U.S. Environmental Protection Age ncy) provided written comments on the draft supporting documentation, hazard characterization and dose-response analysis.

The health-related sections of the Assessment Report were reviewed and approved by the Health Protection Branch Risk Management meeting of Health Canada.

The entire Assessment Report was reviewed and approved by the Environment Canada/Health Canada CEPA Management Committee.

A draft of the Assessment Report was made available for a 60-day public comment period (January 22 to March 22, 2000) (Environment Canada and Health Canada, 2000). Following consideration of comments received, the Assessment Report was revised as appropriate. A summary of the comments and their responses is available on the Internet at:

www.ec.gc.ca/cceb1/eng/final/index_e.html

The text of the Assessment Report has been structured to address environmental effects initially (relevant to determination of "toxic" under Paragraphs 64(a) and (b)), followed by effects on human health (relevant to determination of "toxic" under Paragraph 64(c)).

Copies of this Assessment Report are available upon request from:

• Inquiry Centre Environment Canada
  Main Floor, Place Vincent Massey
  351 St. Joseph Blvd.
  Hull, Quebec
  K1A 0H3

or on the Internet at:

www.ec.gc.ca/cceb1/eng/final/index_e.html

Unpublished supporting documentation, which presents additional information, is available upon request from:

• Commercial Chemicals Evaluation Branch
  Environment Canada
  14th Floor, Place Vincent Massey
  351 St. Joseph Blvd.
  Hull, Quebec
  K1A 0H3

or

• Environmental Health Centre
  Room 104
  Health Canada
  Tunney's Pasture
  Ottawa, Ontario
  K1A 0L2