Acrylonitrile is a colorless, volatile liquid with a pungent, onion-like odor. Acrylonitrile is widely used in industry to produce rubber, resins, plastics, elastomers and synthetic fibers and to manufacture carbon fibers used in aircraft, defense and aerospace industries. Exposure to acrylonitrile irritates the mucous membranes and causes a headache, nausea, dizziness, impaired judgment, difficulty breathing, limb weakness, cyanosis, convulsions and collapse. Acrylonitrile is reasonably anticipated to be a human carcinogen and may be associated with an increased risk of developing lung and prostate cancer. Exposure to acrylonitrile is primarily occupational: it is used in the manufacture of acrylic acid and modacrylic fibers. Acute (short-term) exposure of workers to acrylonitrile has been observed to cause mucous membrane irritation, headaches, dizziness, and nausea. No information is available on the reproductive or developmental effects of acrylonitrile in humans. Based on limited evidence in humans and evidence in rats, EPA has classified acrylonitrile as a probable human carcinogen (Group B1).