Benzene was first discovered and isolated from coal tar in the 19th century. Today, benzene is made mostly from petroleum sources. Benzene found in the environment is from both human activities and natural processes. Benzene is also used for the manufacturing of some types of rubbers, lubricants, dyes, detergents, drugs, and pesticides. Benzene is also a natural part of crude oil and gasoline, and cigarette smoke.
Industrial processes are the main sources of benzene in the environment.
Benzene levels in the air increase from emissions from burning coal and oil, benzene waste and storage operations, motor vehicle exhaust, evaporation from gasoline service stations, and use of industrial solvents. Industrial discharge, disposal of products containing benzene, and gasoline leaks from underground storage tanks can release benzene into water and soil. Natural sources of benzene, which include volcanoes and forest fires, also contribute to the presence of benzene in the environment. Benzene can pass into air from water and soil surfaces. Once in the air, benzene reacts with other chemicals and breaks down within a few days.