acrylonitrile
Meaning of acrylonitrile: An industrial building block for acrylic fiber and hard plastics, not a medicine, with a cyanide-releasing breakdown and a contested cancer record.
Definition of acrylonitrile
Acrylonitrile is a colorless, volatile and highly flammable liquid used in industry to make acrylic fibers, hard plastics and synthetic rubber. It has no medical use. Its vapor irritates the eyes and airways, the liquid burns and passes through skin, and part of an absorbed dose is broken down to cyanide, so heavy exposure produces headache, nausea, weakness and collapse.
Where does exposure happen?
Almost entirely at work, and mostly by breathing it.
| Setting | Route |
|---|---|
| Making acrylic fiber and hard plastics | Vapor, and splashes onto skin |
| Fires involving those plastics | Smoke, which also carries hydrogen cyanide |
| Tobacco smoke | A small amount, inhaled |
| Finished plastic articles | Very little, since almost no free starting material remains |
That last row is the reassuring one. The chemical is consumed as the plastic is assembled, so an acrylic sweater or a molded plastic housing is not a meaningful source. Closed handling systems, workplace limits and air monitoring exist because the hazard belongs to the liquid and its vapor rather than to the finished product.
What does it do in the body?
Two things at once. It irritates directly, so the vapor stings the eyes, nose and throat while the liquid burns skin and is absorbed through it. It is also broken down in the liver along a route that releases cyanide, which blocks the ability of cells to use oxygen. Heavy exposure therefore brings headache, nausea, dizziness, weakness and chest tightness, and at the extreme the picture of cyanide poisoning, for which the standard cyanide antidotes are relevant.
Does it cause cancer?
The animal evidence is clear and the human evidence is not. Rats exposed to it reliably develop tumors of the brain and of several other sites, and national review bodies list it on that basis as reasonably anticipated to be a human carcinogen. Studies following exposed workers have been less consistent: the largest have not shown a clear overall excess of lung cancer, and the suggestion of a link with prostate cancer rests on scattered findings rather than a reproduced pattern. A fair summary is that the hazard is established in animals and drives exposure limits, while no specific human cancer has been firmly tied to it.
Also known as
Used in a sentence
The occupational history included prolonged exposure to acrylonitrile in fiber manufacture.
Good to know
Acrylonitrile is an industrial chemical rather than a medicine, and part of an absorbed dose is metabolized to cyanide, so severe exposure is managed as a cyanide exposure as well as a chemical burn.