Styrene

Styrene is primarily used in the production of polystyrene
plastics and resins. Acute (short-term) exposure to styrene in
humans results in mucous membrane and eye irritation, and
gastrointestinal effects. Chronic (long-term) exposure to
styrene in humans results in effects on the central nervous
system (CNS), such as headache, fatigue, weakness, and
depression, CSN dysfunction, hearing loss, and peripheral
neuropathy. Human studies are inconclusive on the reproductive
and developmental effects of styrene; several studies did not
report an increase in developmental effects in women who worked
in the plastics industry, while an increased frequency of
spontaneous abortions and decreased frequency of births were
reported in another study. Several epidemiologic studies suggest
there may be an association between styrene exposure and an
increased risk of leukemia and lymphoma. However, the evidence is
inconclusive due to confounding factors. EPA's Office of
Research and Development has updated previous assessments on the
carcinogenic potential of styrene and concluded that styrene is
appropriately classified in Group C, "possible human carcinogen."
However, EPA has not yet given a formal carcinogen classification
to styrene.