Benzene is a colorless liquid chemical compound characterized by a sweet odor. It is a highly flammable substance that evaporates quickly and dissolves slightly in water. This compound is widely recognized for its association with various health concerns, particularly its established link to certain types of cancer.
Common Sources of Benzene
Individuals can encounter benzene in numerous environments and products, both outdoors and indoors. Industrial activities are significant contributors to benzene levels in the environment. Petroleum refining, chemical manufacturing, and the production of rubber, plastics, dyes, and detergents all involve the use or creation of benzene.
Beyond industrial settings, everyday sources account for a substantial portion of public exposure. Gasoline and vehicle exhaust are common culprits, with emissions from burning coal and oil also contributing to atmospheric benzene. Evaporation from gasoline service stations and heavy traffic areas can lead to elevated levels of benzene in the air.
Indoors, sources like cigarette smoke are particularly impactful, accounting for nearly half of benzene exposure in the United States. Products such as glues, paints, furniture wax, and certain cleaning agents and art supplies can also release benzene vapors into enclosed spaces.
How Benzene Leads to Cancer
Benzene primarily enters the human body through inhalation, though skin absorption and ingestion are also possible routes of exposure. Once in the bloodstream, benzene travels throughout the body and can be temporarily stored in tissues like bone marrow and fat. The body then processes benzene, mainly in the liver and bone marrow, converting it into various products called metabolites.
These metabolites, not benzene itself, are largely responsible for the harmful effects, including genotoxicity. They can damage DNA by inducing oxidative stress and creating reactive oxygen species, leading to DNA strand breaks and mutations. This DNA damage can disrupt normal cellular processes, particularly in the bone marrow, where blood cells are produced. The accumulation of these genetic alterations can impair blood cell production or lead to uncontrolled cell growth, setting the stage for cancer development.
Cancers Associated with Benzene
Exposure to benzene has a strong association with an increased risk of specific types of cancer, primarily those affecting blood and bone marrow. Acute Myeloid Leukemia (AML) is the most consistently and strongly linked cancer to benzene exposure, with numerous studies of workers demonstrating higher rates of AML. Benzene can cause chromosome changes in bone marrow cells, which are frequently observed in human leukemia.
Other blood and bone marrow cancers also show associations with benzene exposure. These include Myelodysplastic Syndromes (MDS), which are conditions where the bone marrow does not produce enough healthy blood cells. Acute Lymphocytic Leukemia (ALL) and Chronic Lymphocytic Leukemia (CLL) have also been suggested in some studies, though the evidence is not as strong as for AML. Non-Hodgkin Lymphoma, a group of cancers that start in lymphocytes, has also been causally linked to benzene exposure, particularly diffuse large B-cell lymphoma.
Reducing Benzene Exposure
Minimizing exposure to benzene involves several practical steps for the general public. Avoiding tobacco smoke, both firsthand and secondhand, is a significant measure, as cigarette smoke accounts for a substantial portion of benzene exposure. If you smoke, quitting is an important step to reduce your daily intake of benzene and other harmful chemicals.
When using products that may contain benzene, such as certain glues, paints, solvents, or art supplies, ensuring good ventilation is important to disperse airborne contaminants. Using these products in well-ventilated areas or outdoors can help limit inhalation exposure. Handling gasoline carefully is also advised; avoid skin contact and try not to breathe in the fumes. Using gas stations equipped with vapor recovery systems can help capture harmful fumes during refueling.
Awareness of potential occupational exposures is also beneficial for those in certain industries. Workers in fields like petroleum refining, chemical production, or those handling industrial solvents may face higher levels of benzene. Employers in these sectors are expected to implement engineering controls like proper ventilation or provide personal protective equipment to limit exposure.