Dupage Policy Journal

The results of new studies into sources of and the potential dangers from ethylene oxide (EtO) gas identify motor vehicles as a primary source of the gas, an entirely different story than media reports over potential health risks from the detection of the gas near the Sterigenics plant in Willowbrook. 

Sterigenics uses EtO to sterilize medical equipment, and news reports over the past year linking the gas to higher cancer rates in the area have whipped up a near panic in the community.

A study by consultant group Ramboll shows that motor vehicles operating just in DuPage County emit many times the levels of EtO that Sterigenics does. Motor vehicles account for approximately 6,800 pounds of EtO emissions per year. Sterigenics was emitting at the rate of 380 pounds per year when the plant was last running. The Illinois EPA shut the plant down in February.

“As the U.S. EPA has already indicated, there are multiple sources of EO in the Willowbrook area,” Phillip Macnabb, president of Sterigenics, said in a statement. “EO emissions from vehicles in DuPage County are approximately 18 times greater than the amount of EO released by the Willowbrook facility, clearly indicating that cars and trucks are a significant contributor to EO levels in the air around Willowbrook.”

Macnabb added that besides cars and trucks, construction and a local diesel generator almost certainly added to EtO levels measured by the EPA

In addition, the results of two studies into the potential health risks of the gas confirm what independent air quality experts have been saying ever since the first news reports linked the gas to cancer: local residents are not at higher risk from contracting cancer due to EtO emitted by the plant.

One study published in the International Journal of Environmental Research and Public Health reevaluated historical exposures to the gas among workers (who are exposed at many times the levels detected in the air around the Sterigenics plant) in the National Institute of Occupational Safety and Health (NIOSH) study cohort.

The U.S. EPA relies on the NIOSH cohort study findings in its 2016 IRIS risk assessment, Sterigenics said in a statement. But the review found that the trend in EtO exposures during the study period was opposite the trend indicated in the NIOSH study “suggesting that the US EPA’s exclusive reliance on the NIOSH cohort to estimate EO cancer risk should be re-examined.”

Another study appearing in The International Archives of Occupational and Environment Health (IAOEH) conducted a systematic literature review and meta-analysis of studies of cancer risks among workers exposed to EtO. Based on their review, the researchers concluded that the most recent and informative studies on the topic “do not support the conclusion that exposure to EtO during production or use in sterilization processes is associated with an increased risk of lymphohematopoietic cancers (LHC) or breast cancer,” Sterigenics said.

The new research supports earlier assessments of Sterigenics and EtO by independent air quality experts. For an earlier story on EtO, Rich Trzupek said the EPA readings “were temporary and spatially limited. You would have to stand in the same spot for 33 years with the wind coming from the same direction to see any increased cancer risk from the levels the EPA found. You have a greater chance of getting sick of dying from thousands of other things.”

Sterigenics has gone to court to get its Willowbrook plant reopened.