First Priority Substances List (PSL1) Assessments

The first Priority Substances List (PSL1) was published in the Canada Gazette in 1989, and the assessments of risks to human health or the environment posed by the 44 substances on the list were completed within the legislated time frame of five years. (Options to reduce exposure for those substances determined to be "toxic" were and are being considered, in consultation with stakeholders.)

PSL1 Substances Considered as "Toxic" under Section 11 of the 1988 Canadian Environmental Protection Act (CEPA 1988)

(These downloadable files have been created with Adobe Acrobat(TM). To view and print these publications, you will need the Adobe Acrobat(TM) Reader, which is a free viewer available from Adobe Systems.)

Other PSL1 Substances Assessed under Section 11 of CEPA (1988)

The basis for the conclusion of the assessments for these 44 substances is described in a Priority Substances List Assessment Report for each substance.

Available data were considered insufficient to conclude whether 7 of the 44 substances on PSL1 were "toxic" to human health under Paragraph 11(c) of CEPA 1988. These seven substances are presented below:

Following release of the PSL1 assessments on these compounds, they were deleted from the Priority Substances List between November 1992 and February 1994.

The Assessment Reports for each of the seven substances on PSL 1 for which a conclusion could not be reached have now been updated based on a comprehensive search to identify recent critical new data. Each of the Assessment Reports briefly reviews the reasons for determining that the available data were "insufficient to conclude" whether these PSL1 substances were "toxic" under CEPA 1988. The information on commercial activity in Canada is updated, and the critical new data that impact on the initial outcome under CEPA 1988 are presented. The impact of these new data on the assessment of "toxic" under CEPA 1999 is assessed, uncertainties are outlined and considerations for follow-up are specified.

Final Assessment Reports for the following substances for which data were insufficient to conclude whether these substances were "toxic" to human health can be downloaded as PDF or HTML files (when finalized versions become available). Hard copies are available from

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