Integrated Framework for the Health-Related Components of Categorization of the Domestic Substances List Under CEPA 1999: Questions & Answers

What is an existing substance under CEPA 1999?

The Canadian Environmental Protection Act, 1999 (CEPA 1999) requires the federal Ministers of the Environment and of Health to identify and determine which existing substances already in the environment pose a risk to human health and/or the environment. Existing substances include those in an inventory known as the Domestic Substances List (DSL), published in 1994.

The DSL is a compilation of about 23 000 substances used, imported or manufactured in Canada for commercial purposes between January 1, 1984, and December 31, 1986, at a quantity of greater than 100 kg per year. It includes discrete organic compounds, inorganic substances, organometallic substances, polymers and unknown or variable composition complex reaction products or biological material (UVCBs).

Substances that are not listed on the DSL are considered to be new to Canada.¹ The DSL is periodically amended to add substances that have met the listing requirements under the New Substances Notification Regulations of CEPA1999.

How are existing substances selected for consideration under CEPA 1999?

CEPA 1999 specifies a number of ways in which existing substances can be identified for risk assessment. These are:

• categorization of substances on the DSL (Section 73);
  
  
• review of decisions of other jurisdictions (Section 75); and
  
  
• requests for addition to the Priority Substances List (PSL) made directly to the Minister of the Environment (Section 76).

The requirement to which this proposal relates (namely, categorization of substances on the DSL) represents, therefore, only one of the ways in which substances for which there is a need for assessment of risk with respect to human health and/or the environment can be brought to the attention of the Ministers/departments.

What is categorization?

CEPA 1999 requires the Ministers, within seven years from Royal Assent of the Act, to categorize all substances on the DSL to identify those that may present, to individuals in Canada, the greatest potential for exposure (GPE) or those that are persistent (P) and/or bioaccumulative (B) and inherently toxic to humans (IThuman) or to non-human organisms (ITeco). A final list of substances identified by categorization will be published by the legally mandated deadline of September 13, 2006, and each substance on the list will subsequently undergo a screening assessment to consider potential risk to human health and the environment.

What is the role of the Minister of Health in categorization under CEPA 1999?

There are two aspects of the requirement to categorize substances on the DSL relevant to human health. Under Paragraph 73(1)(a) of CEPA 1999, GPE substances on the DSL must be identified. The Minister of Health is also responsible for identifying a subset of substances on the DSL that are priorities for risk assessment based on designation as IThuman.

How does this proposal contribute to Health Canada's responsibility for categorization under CEPA 1999?

This proposal describes an integrated framework for the identification and prioritization of substances for subsequent screening assessment based upon the requirements under Section 73 of CEPA 1999 to categorize substances on the DSL for GPE and IThuman. It addresses all substances through the application of simple and complex tools to assess human exposure and to identify potential hazards to human health.

This is the second proposal related to Health Canada's responsibilities for categorization of the DSL under CEPA 1999 that has been issued for public comment. Based on comments and information received in response to this proposal, and taking into account additional stages of refinement that continue to be developed, a finalized integrated framework for categorization for both GPE and IThuman will be developed. This framework and associated prioritized substances will be integrated with the approach and priorities for assessment from an environmental perspective prior to the 2006 mandated deadline for DSL categorization.

How does this proposal relate to an earlier one on "greatest potential for exposure" released by Health Canada in the autumn of 2003?

This proposal describes an integrated framework for the identification and prioritization of substances for subsequent screening assessment based upon the requirements under CEPA 1999 to categorize substances on the DSL for both GPE and IThuman.

The earlier proposal on GPE described an approach to the first stage of identification of priorities for further work in relation to the requirement under CEPA 1999 to categorize substances on the DSL for GPE only. This earlier proposal represents essentially the simple exposure tool (SimET) referred to in this proposed integrated framework.

By what process have these proposals been developed?

The proposed approach to designation of priorities for further consideration in this proposal and the associated maximal list have been developed based on the legislative construct of CEPA 1999, program experience and external input.

Stages of external input included peer input, consultation and review of technical components of the proposed methodology. These stages are distinct from those for consultation with stakeholders and the public.

Peer input includes interface internationally to access forward-looking peer-reviewed methodology addressing critical areas from all sectors and meetings to solicit information and comment at an early stage on the complex, progressive technical components. As the technical components are additionally developed, they are considered in peer consultation and review meetings, which are open to the public. Panels for these meetings are selected by an independent third party who also considers declarations related to potential conflict of interest. There is provision at the meetings for the submission or presentation of information from interested or knowledgeable parties, and meetings are advertised.

In addition to the various peer input and consultation sessions, there is continuing internal quality control auditing of proposed decisions regarding prioritization of individual compounds for further consideration in screening. There have also been several analyses based principally on the outcomes for the Priority Substances assessments of the predictivity or robustness of the tools described in the proposal for the integrated framework.

Critical elements of consultation on the Health Canada components of categorization distinct from those associated with peer review of technical components include public comment on robust proposals and associated preliminary summaries posted on the Existing Substances Division web site (http://www.hc-sc.gc.ca/ewh-semt/contaminants/existsub/index-eng.php). Feedback at information sessions with all stakeholders is also critical.

What aspects of human exposure does Health Canada consider under CEPA 1999?

Health Canada assesses potential exposure of the general population to existing substances from all routes (that is, inhalation, ingestion and contact on the skin) and all possible sources (that is, ambient and indoor air, drinking water, foodstuffs, breast milk for infants, soil and household and consumer products). The purview of CEPA 1999 is restricted to the general environment, and, as a result, occupational exposure is not considered.

What potential effects on human health does Health Canada consider under CEPA 1999?

Health hazards considered include the ability of substances to induce cancer, damage genetic material, cause birth and developmental defects, disrupt reproduction, affect the immune system, cause significant and long-term changes in behaviour or cause damage to individual organs or tissues (such as the lungs or liver). These hazards are evaluated based on studies of toxicity in mammals following short-, medium- and/or long-term exposures and clinical and epidemiological investigations in humans.

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¹ Substances new to Canada after December 31, 1986, are assessed under the new substances provisions of CEPA 1999.