Air testing conducted this fall around a Covington industrial facility found elevated levels of ethylene oxide, a carcinogenic gas used to sterilize medical equipment.
Becton Dickinson entered into a consent order with the state of Georgia earlier this year after a different set of air tests found levels of the gas the state Environmental Protection Division deemed "deeply troubling."
The results of more recent air sampling, conducted in October and November, were lower than the levels that prompted state action. But they were still above the screening level federal regulators use to calculate potential long-term increased cancer risk.
The recent testing was conducted and posted online by the EPD.
“This variation in monitored values should not be alarming,” wrote Michael Dourson, a toxicologist hired by BD who responded to questions on the company’s behalf. “Moreover, the toxicity values are based on high exposures for a lifetime. The occasional high reading (within limits) is of no consequence to the health of folks in Covington.”
Dourson, a consultant, was nominated in 2017 by President Donald Trump to lead the federal government's chemical safety division. Dourson withdrew his name from consideration in the face of bipartisan opposition following the release of hundreds of pages of his correspondence with the chemical industry.
Richard Peltier, an expert in air pollution exposure at the University of Massachusetts, Amherst, cautioned that it was very difficult to draw conclusions based on the limited data published by the state.
Notably, he said the state failed to provide wind speed and direction for testing sites. This information is especially important when trying to parse sources of ethylene oxide from background levels. Some sampling sites are listed as both upwind and downwind, he pointed out.
“Releasing the data like this is either laziness, indifference, or meant to intentionally confuse the public,” Peltier wrote in an email.
Kevin Chambers, a spokesman for the EPD, said the state’s air monitoring shows large variations in the data from week to week and at each sampling location.
“We understand the need to process the data in a way that facilitates an easy reading and interpretation of the data,” he wrote in an email. “We continue to seek ways to better present the data, including adding specific wind direction information on the day of sampling.”
Federal regulators say lifetime exposure to anything higher than 0.02 micrograms of ethylene oxide per cubic meter could result in more than 100 cancer cases per million people, the agency’s threshold for establishing an unacceptable cancer risk.
However, this level does not represent an enforceable standard. Rather it is used to set limits on the amount of pollution that industrial sources can emit into the air. There is no limit on the amount of ethylene oxide allowed in the outdoor air.
More than 80 samples taken in Covington from October to November averaged .4 micrograms per cubic meter. Eight readings measured 1 microgram per cubic meter or greater, with a high of 2.56.
Only one sample was found to be below the federal screening threshold.
The plant was not fully operational for some of the sampling period: BD temporarily suspended operations for the first week in November in accordance with the consent order.
More limited sampling done over the same period in Cobb County, after a similar sterilizer plant operated by Sterigenics closed there in August, found an average of .29 micrograms per cubic meter. Of about three dozen samples, two showed concentrations of 1 microgram per cubic meter or greater. One sample in Cobb was below the federal screening threshold.
In 2016, the federal government concluded ethylene oxide was a much more potent carcinogen than previously thought and expanded its monitoring efforts. Since then, it has found higher-than-expected background levels across the country.
