INDUSTRIAL CHEMICALS – PROBABLE CARCINOGEN (IARC 2A)
Hydrazine is a clear, colourless liquid.[1,2] It has a distinctive ammonia-like odour and is highly flammable. It may also be referred to as diamine or anhydrous hydrazine. There are numerous other synonyms and product names; see the Hazardous Substances Data Bank (HSDB) for more information.
The International Agency for Research on Cancer (IARC) reviewed the evidence of carcinogenicity for hydrazine in early 2016 and upgraded it to Group 2A, probably carcinogenic to humans. This classification is based on limited evidence in humans that hydrazine causes lung cancer, and sufficient evidence of carcinogenicity in experimental animals. Two studies from the same rocket-testing facility showed an excess incidence of lung cancer among workers estimated as highly exposed to hydrazine. Exposure caused increased incidence of liver and lung tumours in mice and rats, and liver tumours in hamsters. In experimental systems, hydrazine induced oxidative stress and DNA damage.
Additionally, hydrazine is corrosive and skin contact may cause burns and dermatitis.[3,5] Inhalation and ingestion irritate the respiratory and digestive systems, respectively.[2,3] Exposure may also cause central nervous system health effects such as nausea, vomiting, convulsions, tremors, lethargy, seizures, neuritis, and in severe cases, coma.[2,3,5] Long term exposure to hydrazine may cause liver, kidney, and reproductive organ damage.[2,3]
Regulations and Guidelines
Occupational exposure limits (OEL) [6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
|Canadian Jurisdictions||OEL (ppm)|
|Canada Labour Code||0.01 [sk]|
|AB, BC, MB, NB, NL, NS, ON, PE||0.01 [sk]|
|NT, NU, SK||0.01 [sk]
|QC||0.1 [sk, em]|
|Other Jurisdictions||OEL (ppm)|
|ACGIH 2020 TLV||0.01 [sk]|
ppm = parts per million
sk = easily absorbed through the skin
stel = short term exposure limit (15 min. maximum)
em = exposure must be reduced to a minimum
ACGIH = American Conference of Governmental Industrial Hygienists
TLV = threshold limit value (8 hour maximum)
Canadian environmental guidelines
|Cosmetic Ingredient Hotlist||Not permitted for use||2004|
|BC’s Contaminated Sites Regulation, BC Reg 375/96||Sets soil standards for:
Agricultural and low density residential sites: 2.5 μg/g
Urban park and high density residential sites: 4.5 μg/g
Commercial and industrial soil: 10 μg/g
Drinking water standards: 0.05 μg/L
μg/g = micrograms per gram
μg/L = micrograms per litre
|Health Canada||DSL – high priority substance with intermediate potential for exposure||2006|
|Challenge to industry||Batch 10 [Health]||2007|
|CEPA Toxic substances list||Schedule 1, paragraphs ‘b’ and ‘c’||2012|
|Environment Canada’s National Pollutant Release Inventory||Reportable to NPRI if manufactured, processed, or otherwise used at quantities greater than: 1 000 kg. Total of the acid or base and its salts, expressed as the molecular weight of the acid or base.||2016|
DSL = Domestic Substances List
CMP = Chemicals Management Plan
Hydrazine was not included in other Canadian government guidelines, standards, or chemical listings reviewed.
Hydrazine is mainly used as a chemical intermediate to produce agricultural pesticides and blowing agents used in plastic production, and as an anti-corrosion agent in boilers and heating systems.[1,2]
Hydrazine is also used as a chemical intermediate to produce spandex, as a rocket fuel, and as a catalyst or reducing agent in a number of chemical processes.[1,2] It is used to plate metals on glass, in solders and fluxes, in textile dyes, during nuclear fuel processing, as a heat stabilizer, in explosives, and in water treatment and developing chemicals used in photography.
Hydrazine was previously used as a medical treatment for cancer and sickle cell disease.
In Canada, hydrazine is used for the following purposes:
- Antioxidant, corrosion inhibitor, tarnish inhibitor, scavenger, anti-scaling agent
- Chemical intermediate
- Formulation component
- Water or waste treatment chemical
- Agriculture, other
- Organical chemicals, industrial
- Organic chemicals, specialty
- Plating and surface finishing
Environmental Exposures Overview
The majority of hydrazine found in the environment is generated by industry, although it occurs naturally in small amounts in some plants and algae.
In Canada, the most significant source of environmental releases of hydrazine is via effluents from power generation facilities, where hydrazine is used to prevent corrosion in boilers. Emissions and spills or leaks may also occur in industrial plants involved in producing, processing, and applying hydrazine, or during the use of hydrazine fuels.[2,29]
Once released, hydrazine is rapidly oxidized and does not persist in the environment,[2,27,29] therefore public exposures to hydrazine are expected to be low.[1,29]
Some environmental exposure above ambient levels may occur in individuals living near industrial sites that conduct activities involving hydrazine.
Hydrazine has also been found in tobacco products and tobacco smoke at a concentration of 32 µg/cigarette.[1,2] Individuals who chew tobacco, smoke cigarettes, or are exposed to secondhand smoke are exposed to hydrazine.[1,2]
Searches in Environment Canada’s National Pollutant Release Inventory (NPRI) and the United States Consumer Product Information Database yielded the following results on current potential for exposure to hydrazine in Canada:
NPRI and US Consumer Product Information Database
|Substance Name:||‘Hydrazine (and its salts)’|
|Released into Environment||1.9 t||Electric power generation, transmission and distribution; chemical manufacturing (4 facilities)|
|Disposed of||1.3 t|
|Sent to off-site recycling||None|
|US Consumer Products 2016|
|Search Term||Quantity||Product Type|
|‘Hydrazine monohydrochloride’||1||Home maintenance|
t = tonne
Occupational Exposures Overview
Inhalation and dermal contact are the most important routes of occupational exposure to hydrazine.
The main occupations exposed to hydrazine include workers involved in: producing or processing hydrazine, chemical blowing agents, and agricultural chemicals; treating water and maintaining water boiler systems; and applying pesticides.[2,4]
Occupational exposure may also occur during the military use of hydrazine rocket fuel and in the laboratory where hydrazine is used for research or other experimental purposes.[2,3,29]
CAREX Canada has not prioritized Hydrazine for exposure estimate development. This is because there is a lack of exposure monitoring data in the Canadian Workplace Exposure Database on which to base an estimate.
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