Health and Environment
Acute (Short-Term) Health Effects
- Acrylonitrile is lethal at inhaled concentrations around 85 parts per million (ppm).
- Acrylonitrile may induce headaches, dizziness, nausea, vomiting, muscle weakness, convulsions, feelings of apprehension, or nervous irritability at less than lethal levels.
- Acrylonitrile inhalation can also irritate the lungs, causing coughing or shortness of breath, and airborne exposure can irritate the eyes and nose. These symptoms result from acrylonitrile’s ability to inhibit the respiratory action of tissue cells and render them incapable of oxygen absorption.
- If acrylonitrile touches skin, it can cause severe burns, irritation, or blisters.
Chronic (Long-Term) Health Effects
Acrylonitrile is a probable carcinogen and a suspected reproductive toxicant. Since the purposeful testing of chemicals on humans is unethical, the lag time between exposure and effect is long, and the array of confounding factors is often great, solid epidemiological data confirming a chemical’s carcinogenicity is rare. For this reason, government and research agencies identify different levels of carcinogenicity.
Acrylonitrile is a probable carcinogen according to the International Agency for Research on Cancer (a Group 2A carcinogen) and the U.S. Environmental Protection Agency (EPA) (a Group B1 carcinogen).
The U.S. Environmental Protection Agency (EPA) describes the current state of acrylonitrile’s carcinogenicity as follows: “A statistically significant increase in the incidence of lung cancer has been reported in chronically exposed workers. However, many of these studies contain deficiencies such as lack of exposure information, short follow up, and confounding factors. In several studies, an increased incidence of tumors has been observed in rats exposed by inhalation, drinking water, and gavage.”
While no data are available on the reproductive or developmental effects of acrylonitrile in humans, “Fetal malformations have been reported in rats exposed to acrylonitrile by inhalation. In mice orally exposed to acrylonitrile, degenerative changes in testicular tubules and decreased sperm count were observed.”
Facilities using acrylonitrile need to protect worker health by enclosing operations and/or using local exhaust ventilation. If these practices are not implemented, workers need respirators to protect their health. Since acrylonitrile is a probable carcinogen, and there may be no safe level of exposure to a carcinogen, all contact should be reduced to the lowest possible level. Workers also need to wear protective gloves and clothing to avoid skin contact with acrylonitrile.
The legal airborne permissible exposure limit (PEL) for acrylonitrile, set by the Occupational Safety and Health Administration (OSHA), is 2 parts per million (ppm) — averaged over eight hours. The PEL for any 15-minute work period is 10 ppm or less.
Outside the daily routine, leaks, fires, and reactions pose the greatest threat to workers, as acrylonitrile is both a flammable and reactive liquid. During fires poisonous gases form, including hydrogen cyanide, and containers may explode.
Data on the public and ecological exposure to acrylonitrile are scarce because it is an intermediary chemical, soluble in water, and is not persistent or bioaccumulative. As an intermediary chemical, acrylonitrile is typically used in enclosed applications and converted to other materials, resulting in low environmental releases. Soluble in water and absent persistent or bioaccumulative properties, acrylonitrile is seldom identified in drinking water, body fat, or the food chain.
An area of concern has been with the use of acrylonitrile-based polymers in food packaging. For example in 1977, the U.S. Food and Drug Administration (FDA) banned the use of acrylonitrilebased polymers in beverage containers. The FDA’s concern was the leaching of unreacted acrylonitrile monomer into beverages, exposing the general public to small, but constant levels of acrylonitrile. In 1982, the FDA stepped back from the ban and now allows the use of acrylonitrile in food packaging, including non-alcoholic carbonated beverages.