Approximatively 10,000 to 33,000 workers in the EU are exposed to acrylonitrile at their workplaces. Inhalation is considered as the primary route of exposure although workers can be exposed through dermal contact as well as acrylonitrile can readily penetrate the skin.

Acrylonitrile is classified as Carcinogenic Category 1B (according to CLP regulation), which means it is presumed to have carcinogenic potential for humans, based on animal evidence. The exposure to acrylonitrile can cause lung cancer and there is evidence that acrylonitrile can cause bladder cancer.

Where risks occur

The primary use of acrylonitrile is as the raw material for the manufacture of acrylic and modacrylic textile fibres. Other major uses include the manufacture of chemicals, rubber products and plastic products; acrylonitrile and styrene are also used together in the production of styrene–acrylonitrile (SAN) and acrylonitrile–butadiene–styrene (ABS) resins.

More about the substance

At normal temperature and pressure, acrylonitrile is a clear, colorless liquid that has a pungent odor. Small amounts of acrylonitrile are released during the combustion of plant matter such as biomass, timber and tobacco. Acrylonitrile is widely used in the aircraft, defense, aerospace and automotive sectors.

Hazards that may occur

When breathed in or absorbed via skin contact, the primary target for toxicity is the central nervous system.

Acrylonitrile can also locally irritate skin, eyes and respiratory tract, and skin sensitisation. Part of this toxicity is due to the metabolism of acrylonitrile to cyanide.

At higher exposure levels, acrylonitrile is also associated with other effects such as limb weakness, laboured breathing, dizziness, impaired judgement, cyanosis and nausea, through to collapse, irregular breathing and convulsions, depending on dose and duration of exposure.

Acute inhalation exposure to liquid or vapour forms of acrylonitrile (often occurring as a result of accidental release) has been associated with a range of effects including irritation of the mucous membranes of the nose, eyes and upper respiratory tract.

With regard to the latency period between exposure and acrylonitrile related brain cancer, a 30 years latency period.

What you can do

At the workplace, the most effective way to prevent exposure is by substitution of acrylonitrile, for example in the manufacture of ABS it can be replaced by methacrylonitrile (2-methyl-2-propene-nitrile). Where substitution of acrylonitrile is not possible and use of acrylonitrile cannot be avoided, measures to reduce exposure must be taken.

The most effective way to avoid exposure to acrylonitrile is to develop and use closed systems. Where this is not possible, technical measures such as effective local exhaust ventilation, supplemented by good ventilation of the workplace as well as checking their effectiveness should be implemented to ensure that exposure is minimised as much as technically possible.

Implement regular exposure assessments to check if your protective measures in place are effective or whether further actions need to be taken. Workers need to be aware of the effects of exposure and should be trained regularly on the control measures necessary for working safely with acrylonitrile to prevent exposure. Involving an occupational physician is recommended.

Ensure that workers have adequate personal protective equipment, such as protective clothing and gloves, if necessary. Personal protective equipment should not be used as the only preventive measure. As many of the above technical and organisational measures as possible must have been implemented beforehand. Make sure the right personal protective equipment is used, like eyes and face protection, gloves, protective clothing and breathing protection. In addition, when selecting equipment, the anatomy of the workers who will be using it must be taken into account and, in the case of respiratory protective equipment based on facial adjustment, it is highly recommended that a fit test be carried out on each person. Additionally, all workers should be instructed to wash their hands properly before taking a break or entering another area, and to wash themselves and change their clothes at the end of each shift.

Personal protective equipment should only be used as a last resort and only considered temporarily, after the possible technical solutions have been exhausted. Workers should receive the necessary training and information for the correct use and maintenance of PPE.

References:, CLP, IARC, Impact Assessment, RAC