Since the 1980s, the 85-mile stretch of the Mississippi River connecting New Orleans and Baton Rouge, Louisiana, has been known as “Cancer Alley.” The name stems from the fact that the area’s residents have a 95 percent higher chance of developing cancer than the average American. A big reason for this is the concentration of industrial facilities along the corridor – especially petrochemical manufacturing plants, many of which emit ethylene oxide, an extremely potent toxin considered a carcinogen by the Environmental Protection Agency and linked to breast and lung cancer. .
But while the general risks of living in the region have been clear for decades, the precise dangers are still coming into focus — and the latest data shows that the EPA’s modeling dramatically underestimated the levels of ethylene oxide in southeast Louisiana. Ethylene oxide levels in the heart of Cancer Alley average more than double the threshold above which the EPA considers cancer risk unacceptable, according to a new study published Tuesday.
To gather the new data, Johns Hopkins University researchers ran highly sensitive air monitors along a planned route where a concentration of industrial facilities known to emit ethylene oxide are located. The monitors detected levels as much as 10 times higher than EPA thresholds, and the researchers were able to detect plumes of the toxin spewing from the facilities from as much as seven miles away. The resulting measurements were significantly higher than the EPA and state environmental agency modeled emission values for the area.
“From more than two decades of these measurements, we have always found that the measured concentrations of almost every pollutant are higher than we expect,” said Peter DeCarlo, an associate professor at Johns Hopkins University and an author of the study. “In the case of ethylene oxide, this is particularly important because of the health risks associated with it at such low levels.”
There is no safe level of exposure to ethylene oxide. The EPA calculates exposure thresholds for various chemicals by determining the level at which they cause an increased incidence of cancer. For ethylene oxide, the EPA determined that breathing nearly 11 parts per trillion of the chemical over a lifetime could lead to one additional case of cancer per 10,000 people. The higher the concentration, the greater the risk of cancer.
DeCarlo and his team found that, in three-quarters of the regions where they collected data, ethylene oxide levels were above the 11 parts per trillion threshold. The level averaged around 31 parts per trillion. In some extreme cases, they observed surface averages above 109 parts per trillion. The findings were published in the peer-reviewed academic journal Environmental Science & Technology. The study was partially funded by Bloomberg Philanthropies, which launched a campaign in 2022 to block the construction and expansion of new petrochemical facilities.
“We’ve certainly seen parts per billion levels at the fence line of some of these facilities, which means that people inside the fence line — workers, for example — are exposed to much, much higher concentrations throughout the course of their day,” DeCarlo said. .
Ethylene oxide is released from petrochemical manufacturing and plants that sterilize medical equipment. Earlier this year, the EPA introduced rules for ethylene oxide emissions from both types of facilities. The rule that applies to the Louisiana manufacturing facilities requires companies to install monitors and report data to the EPA and state environmental agency. If the monitors record concentrations above a certain “action level”, companies will be required to make remedial work. The rule is expected to reduce emissions of ethylene oxide and chloroprene, another toxic chemical, by 80 percent. Companies have two years to comply.
Heather McTeer Toney, who heads the campaign against petrochemical facilities at Bloomberg Philanthropies, told Grist in an email that the new measurements provide a baseline understanding as the EPA’s new regulations take effect. “The EPA’s new rule was necessary, but should be just the beginning of how we begin to fix things here,” she said. “I’m hopeful to see levels coming down, but the data suggests we have a long way to go.”
Tracey Woodruff, a professor who studies the health impacts of chemicals at the University of California, San Francisco, said the study “confirms that EPA is doing the right thing in regulating ethylene oxide” and that the agency “needs to improve their modeling data “. .” The levels identified by the researchers are 9 times higher than that estimated by the EPA’s models.
For residents in the area, the study’s findings confirm their lived experience. Sharon Lavigne, the founder of Rise St. James, a community organization that supports the expansion of the petrochemical industry in St. James Parish told Grist that the study is “a step in the right direction” and helps the community gain a deeper understanding of what they are exposed to. But ultimately, without accountability and follow-up, monitoring data will do little to help her family and neighbors.
“These monitors are good, but in the meantime people are dying,” she said.
