Health Concerns

Styrene

The primary way styrene may enter the body is by inhalation of contaminated air into the lungs. Studies indicate that approximately two-thirds of the styrene inhaled into human lungs is actually retained (ATSDR, 1991). The majority of retained styrene is rapidly absorbed from the lungs into the bloodstream where it can then be transported throughout the body.

A small portion of retained styrene leaves the body unchanged through exhaled air. The majority of absorbed styrene is rapidly broken down into other compounds (metabolites) and leaves the body through the urine. Experimental studies indicate that, once exposure has stopped, total elimination of styrene from the body may take a few days up to a few weeks.

Short term inhalation of large amounts of styrene is reported to adversely impact the central nervous system. Depression, concentration problems, muscle weakness, tiredness, and nausea have been reported in people, especially workers, who have inhaled large amounts of styrene for short periods of time (ATSDR, 1991). Exposure to styrene in the air may also irritate the mucous membranes of the eyes, nose and throat.

Some studies of female workers indicate that occupational exposure to elevated air levels of styrene, in a mixture with other potentially hazardous chemicals, may be associated with lower birth weight babies and an increased risk of spontaneous abortions (miscarriages) (ATSDR, 1991). However, it is unknown what role styrene itself may play in these effects.

Rapid recovery from the adverse effects associated with short-term inhalation exposure to styrene vapors has been noted. However, the potential effects of long-term human exposure to low levels of styrene vapors are not currently known.

Experimental studies indicate that animals are also impacted by inhalation of styrene vapors. Changes in the lining of the nose of experimental animals have been noted up to several weeks after exposure has stopped. Although long-term inhalation of high levels of styrene has been associated with adverse liver effects in animals, this effect has not been noted in humans (ATSDR, 1991).

Scant information is available regarding adverse health effects associated with human ingestion of or dermal contact with styrene. Liver, kidney, blood, immune system and nervous system effects have been noted in experimental styrene ingestion studies with laboratory animals. Irritation of the skin and eyes has been noted in experimental dermal studies with rabbits. Styrene has been classified as possibly carcinogenic to humans by the International Agency for Research on Cancer.

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Last Updated: 1/31/03