Toxic Tuesdays

CHEJ highlights several toxic chemicals and the communities fighting to keep their citizens safe from harm.


Benzene is a colorless chemical with a sweet odor that is flammable and presents itself in liquid form at normal temperatures and pressures. It is part of a family of chemicals commonly referred to as volatile organic compounds (VOCs), mainly because they evaporate quickly when exposed to air. Although benzene can be formed and emitted from natural processes, exposure to it comes mostly from human activities.

Benzene is among the 20 most widely used chemicals in the United States. It is used as an industrial chemical in the production of a myriad of products including plastics, resins, synthetic fibers, rubber lubricants, dyes, detergents, drugs, and pesticides. Benzene is also naturally found in crude oil and is a major part of gasoline.

The health effects of benzene include irritation of the body parts in contact with the chemical, immune problems, nervous system conditions, and even certain cancers. Acute symptoms of relatively short-term exposure to benzene include skin, eye, and respiratory tract irritation. Prolonged exposures to even low concentrations of benzene can result in central nervous system depression and arrhythmias, as well as trigger anemia and even compromise the immune system. Finally, it has been long established that benzene exposure can cause many forms of leukemia. The International Agency for Cancer Research (IARC) has classified it as carcinogenic to humans (IARC group 1) since 1979.

Human exposure to benzene in the environment usually takes the form of gasoline fumes, automobile exhaust, emissions from certain factories, and off gassing from some commonly used products. Areas that routinely experience heavy traffic can suffer from dangerous levels of benzene in the air. Benzene can also off gas from certain paints and glues and become concentrated in an indoor environment. Additionally, cigarette smoking and secondhand smoke can account for significant benzene exposure. Finally, industries such as oil and gas can contribute to local benzene pollution greatly.

This is the case of the community in Greeley, Colorado where a fracking well pad was in operation just 1000 feet away from the 4th– 8th grade campus of the Bella Romero Academy. Kids and teachers were being exposed to levels of benzene (emanating from the fracking operations) almost seven times higher than the lifetime safe exposure level for benzene developed by the World Health Organization (WHO). Colorado 350, a local nonprofit working on the issue, reached out to CHEJ for help in analyzing a report by Barrett Engineering on the measured levels of benzene in the school. With our help, Colorado 350 is now asking the city to reinstate air monitors and shut down the fracking operation if benzene levels do not drop below safe levels.

Learn about more toxics


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