United States Environmental Protection Agency Office of Pesticides and Toxic Substances TS-793 Washington D C 20460 v>EPA Benzene— what is it? Why is benzene a problem? Toxics Information Series Benzene First discovered in 1825, benzene has been commercially produced and used since the I860's. It has been produced in large quantities in the U.S. since the 1940's and is used as the basis for many other important chemical compounds. The toxicity of benzene is well- documented. As early as the 1920's, benzene was thought to be associated with leukemia. More recent information has provided stronger evidence of benzene's relationship to human cancer and serious questions are being raised about its potential for producing genetic mutations. These concerns, together with other suspected adverse health effects, have prompted government action to limit public exposure to the chemical. This Information Bulletin addresses the hazards of benzene and describes the efforts of the U.S. Environmental Protection Agency (EPA) and others to safeguard public health from the hazards of benzene. Benzene is a unique organic ring formation made up of hydrogen and carbon molecules. The benzene ring is retained throughout many chemical reactions, rather than being rearranged, as are most compounds. The stability of benzene makes it an important basic ingredient for other chemical compounds. Benzene is used as a constituent in gasoline, in the manufacture of dyes, artificial leathers, linoleum, varnishes, lacquers and medicinal chemicals, and as a solvent in waxes, resins and oils. Some 12.72 billion pounds of benzene were produced in the U.S. in 1979. More than half was used in gasoline production. Although benzene is used throughout the country, it is produced in large volumes in only a few States. Production in Texas alone is more than 50% of the total volume, followed by New York and New Jersey with a combined total of 20%. Other, major producing facilities are located in the north central and midwestern States. Human exposure to benzene is widespread due to the prevalent uses of the chemical. Very easily evaporated, benzene is an air contaminant emitted through factory vents and stacks during handling and storage, as well as from gasoline vapors and auto emissions. It can be absorbed through the skin or inhaled The public can also be exposed to small concentrations of benzene in ------- What is the government doing about this hazard? drinking water since benzene can enter water systems through run-off from gas and oil, industrial spills and dump sites. The presence of benzene in foods—ranging from fruits and vegetables to dairy products, meat, fish and poultry—is well documented. Benzene is suspected of causing nerve damage, blood disorders and cancer in humans, and genetic damage in laboratory animals. When benzene is absorbed by the body, approximately 50% is retained and either stored in fatty tissue or bone marrow or metabolized by the body into a number of different compounds. Toxic effects associated with benzene exposure are thought to be caused by one or more of these metabolic products. Nerve and blood disorders; Acute (exposure to high concentrationsovershorttime intervals) and chronic (exposure to low concentrations over a prolonged time period) benzene poisoning are shown through nerve and blood disorders. The primary acute effects of benzene are on the central nervous system, which can include the following symptoms: confusion, dizziness, tightening of leg "muscles, pressure over the forehead, excitation and finally coma. Chronic exposure to benzene may induce fatigue, dizziness, nausea and loss of appetite, weight loss and weakness in the early stages, as well as chances in the hematopoietic (blood-forming) system. Symptoms of chronic exposure include: pallor, nose- bleeds, .bleeding gums, excessive menstrual bleeding, small hemorrhages in the skin, headache, ,nausea, internal bleeding, and unconsciousness. Damage resulting from benzene exposure is cumulative and permanent. In addition, people exposed to benzene are at a greater risk if they also suffer from anemia, respiratory disease, alcholism, heart disease, kidney disease, or obesity. Cancer: The World Health Organization's Interna- tional Agency for Research on Cancer has identified benzene^ as a human carcinogen. Epidemiological studies have ""shown a relationship, well accepted by the medical community, between benzene exposure and leukemia. Cancer was first, associated with benzene in the 1920's, but a direct relationship was not made until the late 1970's. Genetic damage; Benzene also produces chromosomal changes or mutations in experimental animals. Occupational studies indicate that benzene exposure also causes damage to chromosomes in exposed workers. Several Federal agencies, such as EPA, the Occupational Safety and Health Administration (OSHA), and the Consumer Product Safety Commission this (CPSC), are working to control public exposure to benzene. OSHA set a workplace standard of ten parts benzene to one million parts air (10 ppm) several years ago. Although a recent OSHA regulation designed to reduce levels of benzene in the workplace was overturned by the Supreme Courts, OSHA continues to investigate methods of reducing benzene exposure. ------- CPSC presently requires warning labels on consumer products containing more than five percent benzene. CPSC has determined that benzene is no longer being intentionally added to consumer products and that of the 10% of those products which contain more than 0.1% benzene (as a contaminant), none contain more than 0.25%. EPA listed benzene as a hazardous air contaminant in 1977, and has begun controlling benzene air emissions from major industries and other stationary sources. The agency has proposed a limit on benzene emissions from maleic anhydride plants, the largest stationary source of benzene air contamination, which should reduce such emissions by 97%. EPA has also proposed emission limits for ethylbenzene/styrene plants, benzene storage and handling, and chemical plant fugitive emissions. Plans are also underway to control coke by-product plants. Benzene is also identified as one of the chemicals on EPA's list of priority water pollutants. Final water quality criteria for benzene were published by EPA in November 1980. These criteria include the latest scientific information on health effects and sources of benzene pollution, and can be used as the basis f c r regulation of water pollution sources by EPA and the individual states. EPA has also proposed regulation of several benzene compounds under the authority of the Clean Water Act in order to reduce the discharge of benzene into the nation's waterways. EPA has obtained voluntary cancellations under FIFRA for all pesticide products containing benzene as an active ingredient. However, benzene could still be contained in certain pesticide products as a contaminant of petroleum distillates or as an inert ingredient. Waste products from benzene production are cited as hazardous, and therefore are subject to regulation by EPA under the Resource Conservation and Recovery Act (RCRA). EPA and the Department of Transportation have each issued regulations governing the transportation of benzene and benzene wastes, including labeling and container requirements and a manifest system for tracking hazardous wastes from point of generation to final disposal. In Summary: Benzene remains a major cause for concern because of its wide usage and its known carcinogenic and possible mutagenic effects in humans. Federal agencies are continuing to research the health effects of benzene and to formulate regulations which will reduce the public's exposure to the substance. ------- |