Priority Substances List Assessment Report for
2-Buthoxyethanol

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 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 2-butoxyethanol (along with 2-methoxyethanol and 2-ethoxyethanol) provided by the Ministers' Expert Advisory Panel on the Second Priority Substances List (Ministers' Expert Advisory Panel, 1995) was as follows:

Potential sources of exposure to these compounds include releases from various industrial and consumer uses. These compounds are widely used as solvents in paints and protective coatings; in printing inks, industrial solvents and cleaners; in the production of plasticizers; as a de-icer in fuels and automotive brake fluids; and in electronics manufacturing. Effects due to exposure include disorders of the central nervous system, blood system, kidneys and liver in both humans and animals. An assessment is required to determine the presence of these substances in the Canadian environment, exposure and the potential risks to human health.

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
K1A 0H3

An electronic version (PDF file) may be requested from: PSL.LSIP@ec.gc.ca. 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 Safe Environments Program (formerly 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:

• Existing Substances Division
  Health Canada
  Environmental Health Centre
  Tunney's Pasture
  Address Locator 0801C2
  Ottawa, Ontario
  K1A 0L2

or on the Safe Environments Program (formerly the Environmental Health Directorate) publications web site (www.hc-sc.gc.ca/hecs-sesc/exsd/psap.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 Existing Substances Division web site (www.hc-sc.gc.ca/exsd-dse) 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 the assessment of entry, environmental fate and exposure, and potential effects on the environment (prior to October 1999) as well as assessment of potential human exposure and health effects (prior to October 1999) are presented in Appendix A. Review articles were consulted where appropriate. However, all original studies that form the basis for determining whether 2-butoxyethanol 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 the Assessment Report related to the environmental assessment of 2-butoxyethanol and the environmental Supporting Document (Environment Canada, 1999) were prepared or reviewed by the following members of the Environmental Resource Group, established by Environment Canada to support the environmental assessment:

• D. Boersma, Environment Canada
• R. Breton, Environment Canada
• P. Cureton, Environment Canada
• N. Davidson, Environment Canada
• R. Desjardins, Environment Canada
• L. Hamel, Union Carbide Canada Inc.
• B. Lee, Environment Canada
• S. Lewis, American Chemistry Council
• B. Sebastien, Environment Canada
• K. Taylor, Environment Canada (lead for the environmental assessment)

Sections of the Assessment Report relevant to the environmental assessment and the environmental Supporting Document were also reviewed by C. Staples (Assessment Technologies Inc.).

A summary of data relevant to assessment of the potential risk to human health associated with exposure to 2-butoxyethanol was prepared in 1996 by BIBRA Toxicology International. Additional recent reviews were also used for the identification of relevant data, including those prepared for the International Programme on Chemical Safety (IPCS, 1998) and the Agency for Toxic Substances and Disease Registry (ATSDR, 1998). Additional and more recent data have been identified through searching the on-line databases listed in Appendix A.

Sections of the Assessment Report related to human health and the relevant supporting documentation were prepared by the following staff of Health Canada:

• K. Hughes
• M.E. Meek
• D. Moir
• L. Turner
• M. Walker

H. Atkins (Ottawa Hospital, General Campus) provided advice on the biological significance of hematological effects. A. Renwick (University of Southampton) provided advice on the adequacy of data as a basis for replacement of default components of uncertainty factors. Input on this aspect was also received at a workshop of the International Programme on Chemical Safety on uncertainty and variability in risk assessment, held in Berlin, Germany, on May 9-11, 2000.

Comments primarily on the adequacy of coverage in the sections of the supporting documentation related to health effects were provided in a written review by members of the American Chemistry Council Ethylene Glycol Ethers Panel, including:

• R. Boatman, Eastman Kodak (for Eastman Chemical)
• R. Gingell, Shell Chemical
• S. Lewis, American Chemistry Council
• A. Schumann, Dow Chemical
• T. Tyler, Union Carbide Corporation

Comments on accuracy of reporting, adequacy of coverage and defensibility of conclusions with respect to hazard characterization were provided in written review by BIBRA International and H. Atkins (Ottawa Hospital, General Campus).

Accuracy of reporting, adequacy of coverage and defensibility of conclusions with respect to hazard characterization and exposure-response analyses were considered in written review of the completed Assessment Report by:

• H. Clewell, K.S. Crump Group, Inc., ICF Kaiser International, Inc.
• J. Delic, U.K. Health and Safety Executive
• J. Gift, National Center for Environmental Assessment, U.S. Environmental Protection Agency
• J. Roycoft, National Institute for Environmental Health Sciences

The health-related sections of the Assessment Report were reviewed and approved by the Healthy Environments and Consumer Safety 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 (August 19 to October 18, 2000) (Environment Canada and Health Canada, 2000). Following consideration of comments received, the Assessment Reportwas revised as appropriate. A summary of the comments and responses is available on the Internet at: www.ec.gc.ca/ substances/ese/eng/psap/final/main.cfm. Sections of the revised Assessment Report relevant to human exposure were considered in written review by V.C. Armstrong (consultant), J. Buccini (consultant) and J. Schaum (U.S. Environmental Protection Agency).

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 by emailing:

PSL.LSIP@ec.gc.ca

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

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

or

• Existing Substances Division
  Environmental Health Centre
  Health Canada
  Tunney's Pasture
  Address Locator 0801C2
  Ottawa, Ontario
  K1A 0L2