Researchers find higher levels of dangerous chemical than expected in southeast

Researchers using high-tech air monitoring equipment rolled through an industrialized stretch of southeast Louisiana in mobile labs and found levels of a carcinogen in concentrations as much as 10 times higher than previously estimated, according to a paper published Tuesday in the journal Environmental Science & Technology.

The study by researchers at Johns Hopkins University raises new health concerns for communities that sit among the chemical plants lining a stretch of the Mississippi River between Baton Rouge and New Orleans—dubbed “cancer alley” by environmentalists.

The Environmental Protection Agency considers long-term exposure to inhaled ethylene oxide gas a cancer risk—a stance challenged by the chemical industry. The state of California, which has its own environmental health agency, also lists the chemical as “known to cause cancer and reproductive toxicity” in men and women.

The study also heralds newer technologies that enable better, more accurate measurements of ethylene oxide and other chemicals.

“The instrumentation technology that we have available to us is just much more sensitive and can be put on vans and driven around in ways that you don’t get with regulatory instruments,” said Pete DeCarlo, one of the researchers on the study.

Ethylene oxide is produced in large amounts and used to make a main ingredient in antifreeze and polyester. It’s also used to sterilize food, cosmetics and medical equipment and as a pesticide.

The report comes as the Biden administration has taken steps to lessen people’s exposure to the gas. Earlier this year, EPA announced plans to limit the use of the chemical. And ethylene oxide also figures in a broad order issued in April requiring more than 200 plants nationwide to reduce toxic emissions.

Traditionally, measurements of ethylene oxide have been made by gathering and storing air samples in stainless steel cannisters for later lab analyses. The problem, DeCarlo said, is that storage in the cannisters appears to alter the concentration of the gas.

Current regulatory figures on ethylene oxide levels are based on samples self-reported by the industry. Those numbers, he said, are “anywhere from two to 10 times lower than the values that we measured with our mobile laboratory in Louisiana.”