In the EU, about 2.1 million workers are estimated to be potentially exposed to hydrazine. The primary routes of potential human exposure to hydrazine are inhalation, ingestion, and dermal contact. Hydrazine is classified as category 1B carcinogen according to CLP regulation, meaning that the substance may cause cancer in humans. It may increase the risk of lung, colorectal, nasal and liver cancer.

Where risks occur

Hydrazine is used in the manufacture of pharmaceuticals, agrochemicals, as a chemical blowing agent, in paints, inks and organic dyes, polyurethane coatings, and adhesives. In addition, hydrazine has several direct applications as an oxygen scavenger, a corrosion inhibitor, a reducing agent, and a propellant. Exposure predominantly occurs in the workplace and has been documented in the paper, tire-manufacturing, military, and aerospace industries where hydrazine is either produced or handled for example as a rocket propellant and in the refilling of fighter aircrafts.

More about the substance

Hydrazine is a colorless oily liquid at room temperature with a penetrating ammonia-like odor. Its liquid and vapour are flammable. It is miscible with methyl, ethyl, propyl, and butyl alcohols, slightly miscible with hydrocarbons and halogenated hydrocarbons, and insoluble in chloroform and ether. It is used primarily as a chemical intermediate to produce agricultural chemicals (e.g., pesticides) and chemical blowing agents, polymer additives, polymers, dyes and active pharmaceutical ingredients. Application is known as a corrosion inhibitor, as a flux for soldering, as water-treatment chemical, and as rocket and satellite propellant.

Hazards that may occur

Hydrazine is known to be toxic by skin contact, inhalation and ingestion. The symptoms of acute (short-term) exposure to high levels of hydrazine may include irritation of the eyes, nose, and throat, dizziness, headache, nausea, pulmonary edema, seizures, and coma in humans. Acute exposure can also damage the liver, kidneys, and central nervous system in humans. The liquid is corrosive to skin and eyes and may produce dermatitis from skin contact.

Prolonged exposure may cause lung, colorectal, nasal and liver cancer.

What you can do

Substitution is possible for certain uses, e.g. as corrosion protection and oxygen binding agent in hot water/steam systems or as fluxes. Different formulations as substitute are on the market. The best control measures include enclosed processes. Specific dose pumping systems can help to avoid direct exposure. Further, local exhaust and general ventilation are common measures in place. After these technical solutions have been exhausted, subsequent work practices to be introduced are providing employees with hazard information and training, providing eye wash fountains and emergency showers, washing body parts at the end of the workshift and prohibit eating, smoking or drinking in chemical handling areas. Perform proper exposure measurements continuously so it is known when actions should be taken. Investigate if workers report early symptoms. Workers need to be aware of the effects of exposure.

Personal protective equipment should consist of a mask, glasses, impermeable gloves and clothing. Personal protective equipment (PPE) should only be used as a last resort, after introducing the possible engineering solutions. It has been reported that good practice and the use of appropriate PPE are common measures in the agriculture industry.

Sources: BAuA, CLP, ECHA, IARC, KOM, SCOEL, US EPA