Toxic substances list: hexachlorobenzene (HCB)

Hexachlorobenzene (HCB) has not been used commercially in Canada since 1972, although it is released to the Canadian environment in trace amounts as a by-product from the manufacture and use of chlorinated solvents and pesticides, through long-range transport and deposition, and "in emissions" from incinerators and other industrial processes.

Regulations have been in place for HCB since 2003. Formerly the regulations for HCB focused on the known sources of this substance in Canada. HCB has been prohibited globally under the Stockholm Convention and the Protocol on Persistent Organic Pollutants under the United Nations Convention on Long-Range Transboundary Air Pollution. With the publication of the Prohibition of Certain Toxic Substances Regulations, 2012, Canada has strengthened its controls for HCB in order to ensure continued compliance with international obligations.

CAS (Chemical Abstracts Service) registry number: 118-74-1

Risk assessment


This substance is entering the environment from the following sources:

Strategic options report

Click on the following link to view strategies and actions recommended to manage risks associated with the substance:

Risk management tools

Tools developed to manage risks associated with the substance:

International engagement

For information on Canada's international engagement on these substances, please visit:


Consultation (past and present) on the substance:

Other information


Chemicals Management Division
Environment and Climate Change Canada
Gatineau, QC K1A 0H3


Substances Management Information Line:
Telephone: 1-800-567-1999 (in Canada) or 819-938-3232


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