Ethylene oxide (“EtO”) is an industrially made volatile organic compound and a known human carcinogen. There are few reliable reports of ambient EtO concentrations around production and end-use facilities, however, despite major exposure concerns. 

It is noteworthy that across a region colloquially termed “Cancer Alley,” a large majority (∼68%, per Figure 2b) of the total facility-level air pollutant-related hazard is attributed solely to ethylene oxide, based on EPA RSEI estimates.

We identified EtO plumes up to 11.4 km away from likely sources based on wind direction analysis.

Ten kilometers is the distance used by the EPA to define “fenceline communities.”  The spatial range of plume impacts could even be higher than the upper range that we observed; Yacovitch et al. describe the potential transport of emissions from a source 35 km away.