This webpage is maintained by the Centers for Disease Control and Prevention (CDC). The webpage provides information and resources on Barium. "Benzene is a chemical that is a colorless or light yellow liquid at room temperature. It has a sweet odor and is highly flammable. […] Benzene evaporates into the air very quickly. Its vapor is heavier than air and may sink into low-lying areas. […] Benzene dissolves only slightly in water and will float on top of water. […] Benzene is formed from both natural processes and human activities. […] Natural sources of benzene include volcanoes and forest fires. Benzene is also a natural part of crude oil, gasoline, and cigarette smoke. […] Benzene is widely used in the United States. It ranks in the top 20 chemicals for production volume. […] Some industries use benzene to make other chemicals that are used to make plastics, resins, and nylon and synthetic fibers. Benzene is also used to make some types of lubricants, rubbers, dyes, detergents, drugs, and pesticides."
Centers for Disease Control and Prevention: http://www.cdc.gov/