Maybe this will help ........................
An ounce of prevention is worth a ton of treatment.
Benzene is among the 20 most widely used chemicals in the United States. It is used mainly as a starting material in making other chemicals, including plastics, lubricants, rubbers, dyes, detergents, drugs, and pesticides. In the past it was also commonly used as an industrial solvent (a substance that can dissolve or extract other substances) and as a gasoline additive, but these uses have been greatly reduced in recent decades.
Benzene is also a natural part of crude oil and gasoline (and therefore motor vehicle exhaust), as well as cigarette smoke.
Cigarette smoking and secondhand smoke are important sources of exposure to benzene. Cigarette smoke accounts for about half of the exposure to benzene in the United States. Benzene levels in rooms containing tobacco smoke can be many times higher than normal.

............................ so although most of us are conditioned to associate smoking primarily with lung cancer, the benzene ring is a poison that has been linked to blood cancers.
Long-term (a year or more) exposure to benzene can produce changes in the blood. It decreases red blood cells and damages bone marrow. This puts people at risk for aplastic anemia and excessive bleeding.
Benzene is associated with an increased risk of leukemia, specifically, acute myeloid leukemia. There is concern that benzene may also contribute to acute and chronic lymphocytic leukemia, non-Hodgkin's lymphoma and multiple myeloma.
Benzene exposure can weaken the immune system because it also damages white blood cells. This puts people at risk for more infections.