Toxic substances list: dioxins

Polychlorinated dibenzodioxins (dioxins) are highly persistent compounds with a strong affinity for sediments and a high potential for accumulating in biological tissues. They have been found in all compartments of the ecosystem, including: air, water, soil, sediments, animals and foods. Up to the nineties, dioxins and furans entered the environment as complex mixtures from four major sources: commercial chemicals (eg. pentachlorophenol); incineration; pulp and paper mills that use chlorine bleaching; and both accidental fires and spills involving polychlorinated biphenyls. Since then, the implementation of several instruments has been successful in reducing over 80% of dioxins releases in Canada.  Currently, the remaining key sources include conical waste incinerators, open burning and thermal processes in metallurgical sectors. 

For information on Canada's international engagement on this substance, please visit:

There is more than one CAS number that applies to this group of substances.

Risk Assessment


This substance is entering the environment from the following source(s):

Risk Management Tool(s)

Tool(s) developed to manage risks associated with the substance:


Consultation (past and present) on the substance:  

Other Information


Substances Management Information Line
Chemicals Management Plan
Gatineau, QC K1A 0H3
Telephone: 1-800-567-1999 (in Canada) or 819-938-3232
Fax: 819-938-3231

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