For months now, Sharon Lavigne, a former special education teacher turned environmentalist, has told just about everyone she meets of the dangers posed if a planned plastics plant is built near her home just outside New Orleans in Louisiana’s notorious “Cancer Alley.”

The founder of a local environmental group, Lavigne, 72, is worried about a proposed facility for the Taiwan-based Formosa Plastics Corp. that is expected to emit 7.7 tons of the cancer-causing ethylene oxide per year, along with greenhouse gases and other air pollutants.

“I want the world to know what’s going on,” Lavigne told a virtual town hall meeting of environmentalists on Juneteenth. “Allowing so much pollution to be released would harm our health and well-being. Polluting industries have already given my parish the statistics of having more cancer-causing chemicals than 99 percent of the industrialized area of this country.”

According to researchers at Johns Hopkins University, those chemicals are present in Cancer Alley at rates that are far higher than previously believed. Using state-of-the-art mobile air monitors, environmental engineers identified plumes of the toxic gas ethylene oxide at the fenceline of facilities that in some cases were more than 1,000 times higher than what the U.S. Environmental Protection Agency considers an “acceptable risk.”

The research team’s findings, published recently in the journal Environmental Science & Technology, noted that the EPA’s acceptable threshold for long-term exposure to ethylene oxide is 10.9 parts per trillion. 

But researchers found an average exposure level nearly three times that amount, 31.4 parts per trillion, when they tested the air across Cancer Alley. The bleak nickname refers to the 85-mile stretch of land from New Orleans to Baton Rouge that is home to roughly 200 petrochemical plants and some of the highest rates of cancer in the nation.

The research was funded by Bloomberg Philanthropies’ Beyond Petrochemicals Campaign. Heather McTeer Toney, executive director of the campaign, said the figures from the study are “sobering” and give people a more accurate understanding of the region’s pollution. “I hope that people take away that things are a lot worse than what we thought, than what any of us ever realized,” she said. 

“For people who live in the state, it’s a validation,” McTeer Toney added. “People who live in places that are right under the umbrella of where these polluting entities and petrochemical facilities sit, they’ve been saying for years that ‘this is poisoning us, it’s making us sick and that we’re not getting a real picture of what the impact is to human health as well as to climate and the environment.’”

The exposure levels the team found were substantially above the EPA’s own estimates for the area—which were too high already.

The EPA models the levels of hazardous air pollutants based on emission figures provided by state officials, who rely on petrochemical plant operators to report that data themselves. For years, advocates have warned that this method underestimates pollution and health risks. The Johns Hopkins researchers said their findings indicate dramatic miscalculations. 

Self-reported data “seem to underestimate the concentrations of ethylene oxide that we observed in this part of Louisiana,” said the study’s senior author, Peter DeCarlo, an associate professor in the Department of Environmental Health and Engineering at Johns Hopkins. “Why that’s important is they exceeded it by quite a bit, sometimes up to 20 times, when we look at the census tract level. And that means the cancer risk in this area—which is already called Cancer Alley—is significantly underestimated by that same factor.”

Ethylene oxide, which is used to sterilize medical equipment and other items, is a key ingredient in the production of plastics. It is also, as DeCarlo noted, “a pretty strong carcinogen.”

Ellis Robinson, one of DeCarlo’s co-researchers, said few accurate assessments of ethylene oxide exposure exist because measuring the substance is difficult. The John Hopkins team worked around that in part by driving around southeastern Louisiana and testing air samples from a mobile lab.

“The way that I think our measurements fit into the broader picture is that I can’t emphasize enough how—in many areas and contexts—we’re kind of just flying blind when it comes to ethylene oxide,” Robinson said, referring both to scientists and regulators. 

“We don’t have a great sense for how much is in the atmosphere, how much people are actually breathing,” he added. “So what I think our study does is it provides the first data points in this area. It demonstrates that the levels are such that there should be concern.”

In a statement, the American Chemistry Council, a lobbying group, said the study’s analysis fundamentally misrepresents information about ethylene oxide emissions in the area.

The statement said the study “inappropriately compares its collected sampling data with the separate analysis from EPA’s AirToxScreen database, effectively ‘comparing apples to oranges.’”

In response to the statement, DeCarlo said, “Our measurement comparison to modeled values from Air Toxics Screening assessment is an appropriate comparison and not ‘apples to oranges.’”

DeCarlo said he hopes data about the levels of toxic substances in the area can play a role in the decision-making that goes into permitting and regulating industrial facilities.

“I’m an academic researcher, and I like to measure things in the air, but I think systematically it should be done by our regulatory agencies,” DeCarlo said. “What people in the area are being exposed to really should play a better role in how we decide to permit new facilities, or give permits for facilities that already exist.”

He added: “The level of ethylene oxide that we saw was higher than what we consider normal or safe. And that indicates there really shouldn’t be any additional pollution sources or burdens in that area.”

That has long been the position of environmental advocates in Louisiana like Lavigne. But even as she battles the Formosa plant, she’s concerned that the EPA’s efforts to strengthen regulatory guidelines might not withstand a legal challenge to the agency’s ability to remedy environmental harms that trace back to systemic racism.

Lavigne is African American, as are roughly 40 percent of the 1.6 million residents of the parishes that make up Cancer Alley.

“My community and my family and I cannot afford to breathe and face more exposure to toxic air pollution,” Lavigne told the virtual town hall meeting. “If anything, we need stronger national standards.”

Protective guidelines, Lavigne said, are essential because “these facilities must be required to comply with the rules, because it is simply not right to allow them to sacrifice our lives to make plastics, and to make a profit.”

DeCarlo said there’s far more research to be done on the region’s air pollutants. His team focused on Louisiana because of its dense industrial corridor, measuring about 45 hazardous substances. Ethylene oxide was the first write-up, he said, but it won’t be the last.

“We chose to go down there to really get a better idea of what is in the air,” he said.

For Jo Banner, co-founder of the Descendants Project—a nonprofit organization based in the heart of Cancer Alley—this information matters far beyond Louisiana.

“What happens in Cancer Alley doesn’t stay in Cancer Alley,” said Banner. “We get the first and worst of it, but the big pollutants are … going all over the country, going all over the world. So this impacts everyone’s safety and health. So everyone should be concerned about what’s happening here.”