Commercial sterilization service uses unregulated ethylene oxide vents according to EPA

Sterilization Services of Tennessee, one of the sterilization facilities identified by the EPA as a higher-emitter of the cancer-causing chemical ethylene oxide (EtO), uses three different vents — one of which has been unregulated by the EPA since 2001.

More:EPA identifies potential cancer-causing air pollutant at South Memphis sterilization facility

Venting practices on commercial sterilization centers that use EtO were first regulated in 1994 as a way to limit the concentration of the chemical for the air surrounding a facility. Inhalation is the most common way the public ingests EtO, which has been linked to cancer diagnoses after prolonged exposure.

All three practices, sterilization chamber vents, aeration room vents and chamber exhaust vents, were controlled from 1994 until 2001, when chamber exhaust vents, commonly called back vents, were deregulated.

In 1997, some sterilization facilities using back vents overfed the monitoring machines, causing explosions at some locations. The EPA conducted an investigation and, in 2001, stripped all regulations for back vents. 

An EPA spokesperson confirmed to the Commercial Appeal that Sterilization Services of Tennessee uses back vents, and that emissions from those vents are uncontrolled. 

"We are unsure how much EtO is leaving the back vents, so we used our industry default assumption of 1% EtO use," James Pinkney, a spokesperson for the EPA, said in an email. "In 2021, EtO use at the facility was 145,528 lb, so we assume 1,455 lb is leaving the back vents. The company assumes that 0.03% of EtO use is leaving the back vent (almost two orders or magnitude lower than our assumption), but they did not provide any data supporting this assumption."

Other rooms with vents are also unregulated, Pinkney said, and the EPA is assuming 0.6% of Sterilization Services of Tennessee's EtO usage is emitted through those vents. 

Residents surrounding the facility were mailed a study commissioned by the City of Memphis and the EPA will host a community meeting October 18 to speak with residents about the risk assessment. 

The EPA identified 23 communities with the highest cancer risk, with two being in Tennessee. The other Tennessee-based facility is located in New Tazewell, a rural town north of Knoxville.

Lucas Finton is a news reporter with The Commercial Appeal. He can be reached at Lucas.Finton@commercialappeal.com and followed on Twitter @LucasFinton.