The Myth: Ethylene oxide is a uniquely hazardous manmade compound. It is commonly found at dangerous concentrations in the air, near commercial and industrial facilities that use it, and it is virtually unregulated.

Realty: Ethylene oxide is produced at petrochemical facilities, but is also regularly found in natural, biological systems, such as the human body. It is also commonly found in ambient air throughout industrial, residential, and rural areas. It is one of hundreds of potentially hazardous chemicals that is meticulously regulated by a variety of federal, state, and local agencies, which enforce regulations that are carefully designed to protect human health and the environment.

The Exposure Question

In a world filled with thousands upon thousands of chemicals, natural and manmade, defining “safe” exposure levels to any one of them is an incredibly complex exercise. The risk associated with exposure depends on the state of a person’s health, other exposures and risk factors, the frequency of exposure, genetic predispositions, and many other factors.

One of the more valuable ways of looking at exposure is to compare how exposure to a particular compound near manmade sources differs from natural background exposure in areas far removed from a manmade source. People are generally comfortable accepting the idea that natural background concentrations of air, water, and soil contaminants can serve as a baseline when examining risks associated with exposure. If 10 parts per billion of a compound can be regularly found in the air in remote locations, far away from potential industrial sources, there is no reason to suspect that a similar exposure of 10 parts per billion near an industrial source should be cause for concern.

When examined from this perspective, monitoring efforts in the public and private sectors tell a compelling story about ethylene oxide (EtO). Numerous studies have examined ethylene-oxide concentrations in the ambient air near industrial facilities that use the chemical, such as sterilization operations and petrochemical plants utilizing it as a precursor. These concentrations have been compared to ethylene-oxide concentrations in the ambient air at locations far removed from facilities handling ethylene oxide, and what researchers have found is that there is no meaningful statistical difference between the datasets. The air near a plant handling ethylene oxide is about as likely to contain a slightly higher concentration of the compound compared to Remote Area A as it is to contain a slightly lower concentration of the compound near Remote Area B.