Screening Health Assessment of Existing Substances

In meeting its mission to assist the people of Canada in maintaining and improving their health, Health Canada, through the authority of the Minister of Health, has access to a number of regulatory and non regulatory tools. These include the Canadian Environmental Protection Act, 1999 (CEPA) which is an important part of the Government of Canada's environmental legislation aimed at preventing pollution and protecting human health and the environment.

The Minister of the Environment has overall responsibility for CEPA and works in equal partnership with the Minister of Health in areas where CEPA relates to human health. To meet CEPA responsibilities, the Minister of Health may gather information, conduct investigations and evaluations, including human health screening assessments, for the purpose of assessing whether a substance is entering or may enter the environment under conditions that constitute or may constitute a danger in Canada to human life or health.

As part of Health Canada's activities on existing substances, a human health screening assessment may be conducted on a substance identified from the categorization of the CEPA Domestic Substances List, on a substance meeting criteria outlined under Section 75 of CEPA on actions taken by another Government, on a public nomination to the CEPA Priority Substances List, and on any other substance for which a human health screening assessment is desirable.

These screening health assessments set the stage for either no further action, further in-depth assessment or risk management. They typically involve focused comparison of critical data on exposure and effect i.e., those that have direct impact on either estimates of exposure of the general population in Canada or the measure of dose-response with which estimates of exposure are compared. Critical data are identified based on a comprehensive search and peer review of available data. These assessments involve an iterative approach where, in the first instance, upper bounding estimates of exposure are compared with lowest reported effect levels. The extent of assessment is limited to that necessary to determine that a substance is not a priority for risk management. For substances where margins of exposure are small or for which it is assumed that there is some probability of harm at all levels of exposure for critical effects, comparisons of exposure and effects are refined increasingly taking into account weight of evidence for hazard and mode of action, as necessary, to permit meaningful conclusion and provision of advice for next stages. Data which would permit more definitive conclusion are also identified.

A State of the Science Report on an existing substance presents the technical/scientific basis for the corresponding human health screening assessment. Release of a draft State of the Science Report provides early access to the human health science for the substance, prior to release in the Canada Gazette for public comment of the CEPA draft summary screening assessment and its associated conclusion and/or measure proposed in accordance with relevant Sections and paragraphs of CEPA. (A CEPA summary screening assessment usually consists of both the environmental and human health components).

Depending on the content of the draft State of the Science Report, Health Canada may invite submission of information from relevant industry representatives regarding their existing or planned control measures for the substance(s) addressed in the Report. Health Canada and/or Environment Canada may also initiate consultations with industry representatives concerning such measures.

When notice of a proposed conclusion and/or measure is published in the Canada Gazette, any person may provide to the individual identified therein, written comments on the proposed conclusion and/or measure, as well as on the scientific considerations upon which they are based. Following this comment period, the draft State of the Science Report may be revised as considered appropriate, and the CEPA final summary screening assessment and conclusions and/or proposed measure will be published in the Canada Gazette.

Draft State of the Science Reports have been prepared for the screening health assessment of the following compounds:

Hexachloroethane
Dinitro-o-cresol ( DNOC)
MBMBP
Ethylbenzene
Dibromoethane
Dichloroethene
Quinoline
Biphenyl
MBOCA

Final State of the Science Reports have been prepared for the screening health assessment of the following compounds:

• Polybrominated Diphenyl Ethers (PBDEs)
• Public Comments on and Responses to Public Comments on the Draft Screening Health Assessment Report on PBDEs
• Perfluorooctane Sulfonate, Its Salts and Its Precursors that Contain the C₈F₁₇SO₂ or C₈F₁₇SO₃ Moiety (PFOS)
• Public Comments on and Responses To Public Comments on the Draft Screening Health Assessment on PFOS, Its Salts and its Precursors