Hydrazine is a colourless, fuming oily liquid, with a strong ammonia-like odour. It is dangerously unstable and highly toxic, unless handled in a solution. It occurs naturally as a by-product of microbial nitrogen fixation, and has been found in tobacco smoke. It can also be released into the air during venting operations. Hydrazine has been classified as carcinogenic to human health. [1,2,3,4]
Hydrazine is used across chemical industries as an ingredient in blowing and foaming agents, propellants, and pharmaceutical products. It is used as a precursor to blowing agents and pesticides, and as an ingredient in rocket fuel. Hydrazine is used as a component in some antidepressants.
Routes of Exposure 
Exposure to hydrazine may occur accidentally or occupationally.
Exposure can be from hydrazine-based drugs, or from tobacco.
Workers can also be exposed to the chemical through the handling of propellants or fuel.
The general public can be exposed to hydrazine from a chemical spill.
Hydrazine poisoning affects a range of systems including the integumentary, respiratory and nervous systems.
Acute Effects 
Severity of symptoms depend on the level and type of exposure.
Skin contact with hydrazine can result in severe contact dermatitis and burning eyes, with possible eye damage.
Inhaling the chemical can irritate the nose, throat or lungs. It can also cause pulmonary oedema.
Exposure to hydrazine can cause nausea, vomiting, seizures, dizziness, convulsions and headaches.
Chronic Effects 
Hydrazine is toxic to multiple body systems. Long-term exposure to the chemical can result in cancer. Although there are no long-term studies looking at the effects of hydrazine on humans, animal studies have found that hydrazine caused liver, nasal cavity and lung cancer in animals. Hydrazine may affect reproductive health. Long-term exposure could result in a skin rash, which may be triggered by low dose exposures in the future. Repeated exposure of the chemical can result in bronchitis, anaemia or long-term damage to the kidneys or liver.
~h2First Aid Measures 
- Ingestion: DO NOT INDUCE VOMITING. Rinse mouth, but do not give them anything to drink. Immediately contact a medical professional.
- Skin contact: Immediately wash affected skin with water for at least 15 minutes—then remove contaminated clothing. Do not re-wear until it has been thoroughly de-contaminated. Continue rinsing contaminated skin. Contact a healthcare professional.
- Eye contact: Check for and remove contact lenses if easy to do so. Rinse eyes carefully with water or normal saline solution for 20-30 minutes. Take the victim to a medical centre.
- Inhaled: Take victim to the nearest fresh air source and monitor their breathing. Allow them to rest and contact a medical professional.
- General: Never administer anything by mouth to an unconscious, exposed person.
Exposure Controls/Personal Protection 
Engineering controls: Emergency eyewash fountains and safety showers should be accessible in the immediate area of the potential exposure. Ensure there is adequate ventilation. Whenever possible, material should be handled in a laboratory.
- Personal protection: Safety glasses (indirect-vent, impact and splash resistant), protective and dustproof clothing, glove, an apron and an appropriate mask.
The Occupational Safety and Health Administration (OSHA) has set an 8-hour time weighted average (TWA) concentration for hydrazine of 1ppm.
Safe Work Australia has set an 8-hour time TWA for hydrazine of 0.01ppb.