Toxic substances list: hydrazine

Hydrazine is an industrial chemical primarily used as a corrosion inhibitor in boiler water used at some power generating plants.  Hydrazine is also thought to occur naturally in algae and tobacco plants and is formed during the combustion of tobacco products.  Hydrazine may be released mainly in water, and releases are primarily associated with the maintenance of nuclear and fossil-fuelled power plants when boilers are flushed of their liquids.  Exposure of the general population to hydrazine is expected to be low. 

On January 15, 2011 the Ministers of the Environment and of Health published, in Part I of the Canada Gazette, their final decision on the screening assessment of hydrazine.  It concluded that hydrazine may be entering the environment in a quantity or concentration or under conditions that have or may have an immediate or long-term harmful effect on the environment or its biological diversity and that constitute or may constitute a danger in Canada to human life or health. Based on the conclusions of the assessment, it was recommended that hydrazine be added to the list of toxic substances.  The final order to add hydrazine to Schedule 1 was published October 10 2012.

Summary of risk management actions

Along with the final screening assessment, a Risk Management Approach document was published to explain how risks associated with hydrazine would be managed.

In order to prevent or minimize releases of hydrazine to water, the proposed environmental risk management objective is to achieve the lowest level of releases of hydrazine to water that is technically and economically feasible, taking into consideration socio-economic factors.  In order to work towards achieving the environmental objective, the Government of Canada has developed an instrument to prevent or minimize releases of hydrazine to water from facilities in Canada using boilers to produce steam or electricity where hydrazine is used as a corrosion inhibitor. Specifically, a notice requiring the preparation and implementation of pollution prevention plans with respect to thermal and nuclear power generating facilities using hydrazine has been published.

A Notice of Intent to apply the Significant New Activity provisions to hydrazine was published on March 2, 2013.  Since the implementation and application of the Policy on the use of SNAc provisions of CEPA 1999, published in December of 2013, it was determined that there are no likely new exposure sources of hydrazine for the general population of Canada that would reasonably be suspected to lead to increased risks to human health. Therefore, an Order amending the Domestic Substances List for hydrazine will not be published.

Environment Canada will review and revise risk management controls for hydrazine, if required, as more information becomes available.

For more information on this substance, please visit the Chemical Substances website.

CAS (Chemical Abstract Service) registry number: 302-01-2

Risk assessment

Risk management strategy

Risk management instruments


Substances Management Information Line
Chemicals Management Plan
Environment and Climate Change Canada
Gatineau, QC K1A 0H3

Telephone: 1-800-567-1999 (in Canada) or 819-938-3232
Fax: 819-938-3231

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