Hydrogen sulfide (H2S), sodium sulfide (Na(SH)) and sodium sulfide (Na2S)

Draft screening assessment

In September 2017, the Draft Screening Assessment for Hydrogen Sulfide (H2S), Sodium Sulfide (Na(SH)) and Sodium Sulfide (Na2S) was released and the related notice was published in the Canada Gazette, Part I: Vol. 151 No. 36 – September 9, 2017.

The draft screening assessment proposes to conclude that these 3 substances do not meet any of the criteria set out in section 64 of the Canadian Environmental Protection Act, 1999 (CEPA 1999). Therefore, the Minister of Environment and Climate Change and the Minister of Health propose to take no further action with respect to these substances.

While exposure of the general population to hydrogen sulfide is not a concern at current levels, hydrogen sulfide is associated with health effects of concern (for example, severe neurological effects) at higher concentrations. Therefore, there may be a concern for human health if exposures of Canadians were to increase.

Follow-up activities to track changes in exposure to hydrogen sulfide are being considered.


Date Activity
September 2018 Anticipated publication of the final screening assessment.
September 9, 2017 Publication in Canada Gazette of draft screening assessment (including follow-up activities), and start of 60-day public comment period.
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