Half of the benzene a person inhales is then exhaled. The rest is temporarily stored in the body’s bone marrow and fat. The liver and bone marrow break benzene down into metabolites (the products of physical or chemical processes in the body). Some of these metabolites, such as hydroquinone, are more toxic than benzene. The metabolites are then eliminated from the body after about two days.
Benzene is a carcinogen. While many chemicals are suspected to be cancer-causing, benzene is one of the few substances that have been identified by the Environmental Protection Agency as a “known human carcinogen.” The International Agency for Cancer Research has also determined that benzene is carcinogenic to humans. Occupational studies of workers exposed to benzene have shown that long-term exposure to high levels has caused acute myeloid leukemia. In laboratory studies with rats and mice, benzene has been shown to cause leukemia and other types of cancer.
Benzene can cause neurological damage and can harm the immune system. Long-term exposure to benzene fumes can cause nerve damage. Short-term exposure to high levels of benzene, and to other related aromatic hydrocarbons such as toluene and xylene, can cause dizziness, nausea, headaches, and unconsciousness. Excessive exposure to benzene can harm the immune system.