Healthy Air Oregon Campaign - Benzene Facts

Benzene is a volatile, colorless, highly flammable liquid that is a natural component of crude and refined petroleum. Almost 100% of benzene is commercially derived from petrochemical and petroleum refining industries. It is found in common consumer products such as glues, paints, and marking pens. Benzene is also used in the production of other products, including styrofoam, plastics, various resins, nylon and synthetic fibers.

How does benzene get into the air and into humans?

Benzene is released into the air from emissions from burning coal and oil, gasoline service stations, and motor vehicle exhaust. Other sources include hazardous waste sites, underground gasoline storage tanks that leak, waste water from industries that use benzene, chemical spills, chemical manufacturing sites, and petrochemical and petroleum industries (ATSDR). These sources contribute to elevated levels of benzene in the ambient air, which may subsequently be breathed by the public.

Benzene is brought into the human body primarily through inhalation and can also be absorbed through the skin. In humans, respiratory uptake has been determined to vary from approximately 47% to 80%. For the general public, smoking is the largest human-generated source of benzene exposure. The estimates of daily intake of benzene from a single cigarette vary: from 5.9 to 73.0 micrograms.

How is benzene harmful to health?

The EPA has classified benzene as a Group A, human carcinogen. There is no evidence for a safe threshold level of exposure of benzene. A low-level exposure (2 ppm) increases the risk of leukemia as well as higher levels of exposure.

Benzene has been associated with a variety of maladies from internal bleeding to cancer. Short-term exposure from inhalation can result in drowsiness, dizziness, headaches, tremors, confusion and/or unconsciousness.

Long-term inhalation exposure has caused various disorders including:

• increased incidence of leukemia (cancer of the tissues that form white blood cells)
• damage to blood cells (aplastic anemia) and internal hemorrhaging
• infertility for women
• reduced sperm quality for men
• adverse effects on the developing fetus (observed in animal tests)

Benzene and the link with Childhood Leukemia A strong correlation between childhood leukemia and proximity to gas stations, refineries and automobile traffic has been established by multiple research studies. France’s national research institute recently published a study of 280 children with acute leukemia. Two-thirds of these children were 2-6 years old when diagnosed. The study found that children living near gas stations were four times more likely to have contracted leukemia. These children were seven times more likely to contract Acute Myelogenous Leukemia (AML). Children living for longer periods near a gas station experienced higher rates of leukemia.

Another study in England tracking 22,458 children who died from leukemia or solid cancers found that higher rates of childhood leukemia is associated with living near distributors and industrial users of petroleum products.

A Journal of Occupational Medicine published in 1984 study found that infants whose fathers work at gas stations, a high-exposure occupation, have a higher observed susceptibility to develop acute leukemia. Compared to children of unexposed fathers, children whose fathers were occupationally exposed to benzene and alcohols used in industrial products were nearly 6 times as likely to develop leukemia if the exposure occurred prior to the pregnancy.

Exposure in proximity to gasoline service stations

According to OSHA, the legal exposure limit for breathing benzene is 1ppm in an 8-hour period and 5ppm in any 15 minute period. Exposure to benzene at gas stations can range from 1 – 32 ppm. Gasoline station workers and their families are at risk for exposure to benzene. Customers of gasoline service stations may be significantly exposed even within the confines of their vehicle. People who live in proximity to gasoline service stations are also at risk. Residential exposure has been observed at levels of up to 6.6 parts per billion (ppb) in outdoor areas that are in close proximity to gasoline service stations.

Families living near gas stations or other petroleum product industries can experience long-term effects without ever having short-term effects because repeated long-term effects can occur at levels not high enough to make you immediately sick. This is especially true for children or people who are already ill.

One recent study showed that when gas stations use benzene vapor recovery equipment, attendants have reduced post-shift automobile accidents (less drowsiness and confusion from exposure). The use of vapor recovery devices greatly reduces their level of exposure to benzene.

Vapor-Control Equipment at Gas Stations can Help

What is Stage One Vapor Control equipment? This is a system of valves and gaskets inside the hoses of delivery trucks and the underground gas tanks. The equipment creates a vacuum that recaptures fumes that would otherwise leak to the air when filling the tank. A gas station can easily reduce its gasoline vapors by requiring trucks that fill the station’s underground tanks to use this system. A 1978 law requires gas stations in the Portland metropolitan area, Salem, and Medford with an underground tank capacity of 1,500 gallons to install vapor control equipment. As a result, gasoline delivery trucks have installed the equipment to do business in these three metropolitan areas. However, equipment to control noxious fumes is not required in other cities.