Brenda Goodman is a senior news writer for WebMD. Andy Miller is editor and CEO of Georgia Health News.

The state’s Environmental Protection Division launched an immediate investigation Tuesday of a previously undisclosed leak of toxic gas at a Smyrna medical sterilizing facility.

The amount of the ethylene oxide leaked last month was less than 6 pounds, said Sterigenics, the company that runs the sterilization plant. If it had been more than 10 pounds, the company would have been obligated to report the leak quickly to state regulators.

Candice Broce, a spokeswoman for Gov. Brian Kemp, told GHN that the EPD team was heading to the Sterigenics plant Tuesday evening to assess the equipment there and find out how the company was able to determine the exact amount of the leaked gas.

The news of the leak comes at a time when the Sterigenics plant is facing increased scrutiny from the public and government officials for its releases of ethylene oxide, a cancer-causing gas.

The leak occurred July 31, the day that Sterigenics submitted a permit application to the state for a refitting of the facility to reduce the emissions of ethylene oxide.

And the state investigation follows media reports of an explosion that severely injured a worker at the Sterigenics plant, and of a separate ethylene oxide leak at the facility last year.

The EPD was not told of the severity of the injury to the Sterigenics worker until the Atlanta Journal-Constitution reported on the 2018 accident this week, Broce said.

“We’re concerned the company has a lot of work to do to restore public confidence,’’ Broce said Tuesday evening. “These type of developments don’t help.’’

“It’s a scary story for families in this area,’’ she added.

In addition to the two census tracts in the Smyrna area, the EPA report also flagged one in Covington — along with dozens in other areas of the nation — for higher risks of cancer, driven largely by airborne releases of ethylene oxide.

Just as with Sterigenics in Smyrna, BD Bard in Covington has a sterilization plant that uses ethylene oxide. The chemical, the cancer risks associated with it and the Georgia facilities using the gas were detailed in a report last month by WebMD and Georgia Health News. That report sparked public outrage and scrutiny from officials.

The AJC on Tuesday reported that it obtained a Sterigenics email to employees about the July leak that said “I wanted to inform each of you that we experienced an area evacuation at approximately 3:14 a.m. this morning.”

The email continued: “An investigation took place at this time and it was found that a drum that was recently removed . . . was leaking from the gas valve.”

Sterigenics said in a statement Tuesday that detection sensors alerted employees of a potential release of ethylene oxide.

“Consistent with company procedures, employees properly vacated the area and the incident was immediately investigated,’’ the statement said. “The source of the release was immediately identified and stopped. It was determined that less than six pounds of EO [ethylene oxide] was released from a used EO drum on which the valve was not completely closed after use.

“Although this release was below the level required to be reported to the EPD, Sterigenics took immediate corrective actions to ensure similar incidents do not occur in the future.’’

Earlier this month, the state of Georgia and Sterigenics entered into an agreement known as a consent order to reduce ethylene oxide emissions.

State Sen. Jen Jordan, who represents part of the Smyrna area, said Tuesday that “today’s revelation that Sterigenics failed to disclose yet another leak at its facility just days before it entered into a rushed consent agreement with the state shows why public distrust of the facility is warranted.’’

“The newly discovered leak occurred on the same day that Sterigenics filed its permit application and on the same day that the company’s CEO told hundreds of citizens that it had nothing to worry about. Clearly, they do. If worries about health and safety weren’t enough, area homeowners are starting to see their home values take a hit. When is enough going to be enough?’’

Jordan, in an interview with WABE, called for an investigation into how the EPD has handled the ethylene oxide situation.  The agency declined to comment Tuesday on Jordan’s statement.

Citing the Sterigenics consent order, Gov. Kemp last week also called on BD to come to the table to pledge improvements at its Covington plant to reduce ethylene oxide emissions.