Agents with Georgia Department of Natural Resources’ Environmental Protection Division walk into the Sterigenics facility near Smyrna. State regulators deployed an emergency response team to investigate a toxic gas leak and evacuation that took place there last month, after The Atlanta Journal-Constitution asked state officials if the company had reported the leak. (Hyosub Shin /

State finds no violation in Sterigenics’ July 31 leak of ethylene oxide

Sterigenics was not required to report a toxic gas leak that occurred on July 31 of this year at its Cobb County facility because the amount released fell below state reporting limits, regulators with the Georgia Department of Environmental Protection have concluded.

The finding ends an investigation into the incident opened by the state in late August in response to questions from The Atlanta Journal-Constitution, which had asked regulators if Sterigenics reported the leak.

Sterigenics is permitted to use the gas, ethylene oxide, to sterilize medical devices. In addition to being highly flammable, the chemical was recently reclassified by the federal government as a carcinogen, raising concerns from nearby residents about exposure to emissions.

Those concerns have been amplified by several incidents at the plant, including an explosion in 2018 that seriously injured a worker. The company was also cited by the state for failing to report a separate leak that occurred several months before that.

In August, the AJC obtained an email in which a plant supervisor admonished workers over an ethylene oxide leak on July 31, 2019 that led to an evacuation. That email did not contain details of the leak and when the AJC reached out to EPD officials for comment, the agency dispatched an emergency response team to the facility and opened an investigation.

According to the EPD’s final report posted Thursday, Sterigenics told the agency that an employee had failed to properly close the valve on a nearly empty drum of ethylene oxide. Based on weight, the company said it determined 5.6 pounds of the gas had been lost. A facility is required to report a release of anything greater than 10 pounds, or if the quantity cannot immediately be determined.

Because the leak was determined to be less than 10 pounds, “there is no violation” of Georgia law, the EPD report concluded.

A company spokesman issued a statement thanking the EPD for its “diligent efforts in conducting its investigation.”

“The findings of the EPD’s investigation reaffirm our consistent compliance with applicable rules,” the statement says. “In fact, as disclosed to the EPD, all (ethylene oxide) releases from the facility in aggregate over the past five years were less than the 10-pound reporting threshold for each release.

In the course of its investigation, the EPD also requested data on the past five years of releases, regardless of the amount, from Sterigenics. The agency concluded that all seven of those previously unreported releases were also too small to report.

“Going forward, EPD has requested that the facility send us monthly reports of all known releases, including those below the reportable quantity threshold,” the report says. “The facility has agreed to do so.”

The Cobb plant is currently closed. It suspended operations in August in order to install additional emission controls, but the county has yet to issue a building permit after reclassifying the building from “storage” to “high hazard industrial.”

The reclassification, which comes with stricter fire safety codes, could pose a challenge to the company resuming operations.

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