Summary of comments and responses: addition of precursors to particulate matter, chapter 6

6. CEPA and policy issues

Comment received

The listing of precursor substances is not legally valid or consistent with the Canadian Environmental Protection Act (CEPA) definition of a substance.


The federal government is of the opinion that these substances do meet the definition of a substance under s. 3(1) of CEPA 1999

In addition, a precedent exists for adding precursor substances to Schedule 1. Non-chlorinated dibenzodioxin and dibenzofuran, while not assessed for the risks posed by their direct exposure, were added to Schedule 1 because they can lead to the formation of polychlorinated dioxins and polychlorinated furans, which are toxic under CEPA 1999.

Comment received

An explanation of why section 90 of CEPA was used for the listing rather than section 77 should be provided.


Although Section 77 is often associated with the Priority Substances List (PSL) process, this section of CEPA actually refers to the publication after assessment of a substance. The assessment could include a PSL assessment, a screening level risk assessment or a review of a decision of another jurisdiction.

Since Section 90 refers to the addition of a substance to Schedule 1, a substance being assessed under the provisions of Section 77 would still need to go through Section 90 if it is determined to be a toxic substance. In effect, all toxic substances are added to Schedule 1 under Section 90. However, it is not necessary that all substances be assessed through Section 77. In determining that Section 77 was not required for this listing, a number of factors were considered, including the state of the available science on PM and ozone and the precursors.

In this case, the Ministers' recommendation is based on sound science contained in multi-year, multi-stakeholder, peer-reviewed documents (the PSL Assessment for PM10, the PM SAD and the ozone SAD). An additional assessment under Section 77 for each precursor substance, which would not assess options or set priorities for risk management, would not change the scientific basis for the addition of these substances to Schedule 1.

Comment received

Another listing category should be established under CEPA, such as "Substances to be Managed" to differentiate between substances that are inherently toxic and those that are not.


The creation of a third classification of substances would only be possible through an amendment to the current legislation. CEPA 1999 does not permit the government to make such a distinction through regulation.

It should be noted that CEPA 1999 does provide for a great amount of flexibility in developing risk management measures. Not all substances have to be treated equally under the Act and the extent to which individual substances need to be controlled or managed is determined on a case-by-case basis.

Comment received

CEPA should be amended to allow a substance from a specific source to be listed as toxic instead of having to list the substance as a whole.


This is a suggestion that would require a change to the legislation that is not possible at the current time.

Source identification of toxic substances is an issue that is addressed during the risk management stage and will be considered when developing strategies and preventative or control instruments.

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