In 2016, the U.S. Environmental Protection Agency (EPA) classified ethylene oxide as carcinogenic when inhaled. Despite concerns over chronic exposure in the industrial corridor between Baton Rouge and New Orleans, there were no published reports of ambient concentrations not derived from industry self-reported emissions data. Peter DeCarlo, Department of Environmental Health and Engineering, Johns Hopkins University, Baltimore, and colleagues proposed measuring the levels using optical instruments that quickly measure airborne chemicals in real-time.
Equipped with a mobile monitoring system mounted on a truck, driving a fixed route along the heavily industrialized corridor, the team took over 23 130-mile laps from January to February 2023. The findings resulted in all ethylene oxide measurements being higher than EPA estimates from industry-reported emissions. Most of the region had levels corresponding to risks above EPA's acceptable limit, with a few locations potentially posing serious health risks for facility workers. The team identified chemical plumes up to seven miles from likely sources, beyond the six-mile "fenceline communities" definition.
According to the paper published on the American Chemical Society website, the authors noted: “As other previous mobile monitoring studies have shown, repeatedly capturing measurements of an air pollutant at a location can provide representative concentrations for that location given a sufficient number of visits. Many factors influence the number of visits required for such an ensemble of measurements to paint a representative picture, including time of day, source strength at that location, pollutant type and instrument noise, among others. We designed our sampling to capture 22 or more visits at each location and to be spread across times of day.”
The researchers hope this demonstration of mobile monitoring increases accurate measurements of hazardous air pollution in areas densely populated with emitters, highlighting issues with current detection, reporting methods and associated health impacts on nearby residents.
“It is noteworthy that across a region colloquially termed “Cancer Alley,” a large majority (∼68%) of the total facility-level air pollutant-related hazard is attributed solely to ethylene oxide, based on EPA Risk Screening Environmental Indicators (RSEI) estimates,” the authors of the paper wrote. “We derived this figure from RSEI hazard scores, which are themselves derived from modeled concentrations based on emissions inventories built from industry self-reports; in short, these estimates are likely far from perfect. Nonetheless, the fact that so much of the environmental risk in this area seems to come from a single chemical is remarkable.”
More Coverage on Ethylene Oxide
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EPA Calls for Reduced Ethylene Oxide Emissions
