Louisiana must examine how polluters imperil the health of Black residents, the Environmental Protection Agency said in a letter it sent last week to state regulators in response to civil rights complaints about air pollution in the region known as Cancer Alley.

Black residents in southeastern Louisiana bear a disproportionate cancer risk from industrial air pollution, the agency found, with children at one predominantly Black elementary school having been exposed to a dangerous carcinogen at levels 11 times what the EPA considers acceptable.

ProPublica reported last year that the EPA does a poor job of regulating the combined risk from multiple sources of industrial air pollution. In parts of Cancer Alley, ProPublica estimated lifetime cancer risk is up to 47 times what the EPA deems acceptable.

The EPA letter urged Louisiana’s environmental and health agencies to analyze cumulative impacts for residents near a synthetic rubber plant owned by Denka Performance Elastomer in St. John the Baptist Parish and a proposed Formosa plastics facility in St. James Parish.

Wilma Subra, an environmental health expert who advises communities in the area, said ProPublica’s reporting “confirmed the importance of cumulative risk and made it a focus that could not be ignored.”

“What’s remarkable is that EPA, for the first time in a long time, is speaking the truth around environmental racism and willing to put civil rights enforcement tools out there,” said Monique Harden, assistant director of law and public policy at the Deep South Center for Environmental Justice. Federal civil rights protections predate the EPA, but they haven’t been enforced, she said: “There’s nothing new to any of this except that we have leadership at the EPA” that “wants to do something about it.”

The EPA urged state regulators to move students out of St. John the Baptist Parish’s Fifth Ward Elementary School, where air monitoring found high levels of chloroprene, a potent carcinogen. The letter, which summarizes the agency’s initial findings, cites years of data, studies and state policies to show how Black residents are disproportionately harmed by air pollution and how those disparities are baked into the region’s history. It explains how between the Louisiana Department of Environmental Quality and the Louisiana Department of Health, state officials have dismissed residents’ concerns about air quality, underplayed the dangers of chloroprene, conducted flawed health studies and mischaracterized air monitoring data.

“We take these concerns very seriously and are committed to health equity — which is why we are fully cooperating with the EPA’s investigation into Denka,” the state health department said in a statement.

In an email, an LDEQ spokesperson said the agency is “committed to working with EPA” and remains “confident that we are implementing our air permitting program in a manner that is fully consistent with” federal and state laws.

Local activists have fought for environmental protections for decades. Robert Taylor, executive director of Concerned Citizens of St. John, said he founded his organization after attending a 2016 EPA meeting that revealed chloroprene concentrations at the school. “I went from fear to anger to shock,” he said, that “the government was allowing people to do this.”

The public school is about 1,500 feet from the Denka facility, which produces neoprene, a form of synthetic rubber used to manufacture wetsuits. DuPont began making neoprene at the site in 1969 and sold the neoprene operation to Denka in 2015. It is the nation’s only industrial site that emits chloroprene.

EPA Administrator Michael S. Regan visited the nearby school last fall as part of his “Journey to Justice” trip that was announced two days after ProPublica’s investigation into pollution hot spots. He later sent a letter to Denka and DuPont that stated, “As a parent, I remain extremely concerned” about the “health and well-being of the students.” Three-quarters of Fifth Ward Elementary’s students are Black.

A DuPont spokesperson declined to comment on EPA’s letter to Louisiana regulators but shared a response it sent to Regan in March in response to his letter about the school. In its response, DuPont said that Denka, not DuPont, operates the neoprene facility, and that tens of thousands of residents have worked at DuPont’s adjoining facility. The workers’ children have attended Fifth Ward Elementary, the company said, and “we care deeply about its success.”

DuPont is “committed to continue to work with Denka,” regulators and the community “to maintain the strong ties and supporting efforts needed to keep St. John Parish a safe and great place to work and live,” the company added.

In 2010, the EPA released a report classifying chloroprene as a “likely human carcinogen.” Chloroprene is a mutagen, meaning it causes cancer by attacking and mutating DNA. Mutagens are particularly dangerous for children and infants, whose cells divide much more rapidly than those of adults.

Recent air monitoring data from Denka, collected about 1,000 feet from the school, showed average concentrations 11 times what EPA considers acceptable, according to the agency’s letter. At times over the past few years, air samples collected by the EPA on school grounds showed concentrations as high as 83 times the acceptable guideline.

Jim Harris, a spokesperson for Denka, said in a written statement that the EPA’s chloroprene limit is “based on a faulty and outdated exposure model.”

The company asked the EPA to revise its chloroprene guidelines last year, arguing that the model used was not “sufficiently rigorous.” The EPA refuted Denka’s conclusions this spring, stating that the company did not identify any errors with the agency’s analysis.

“There is simply no evidence of increased levels of health impacts near” the plant, Harris wrote. “Data compiled by the Louisiana Tumor registry (LTR) have repeatedly shown for decades there are no widespread elevated rates of cancer in the parish or in the census tracts neighboring the facility compared with state averages.”

Kim Terrell, a research scientist at the Tulane Environmental Law Clinic, argued that the registry’s census-tract-level data obscures health effects in the communities closest to industrial facilities. The tumor registry, too, has said that its data should not be used to represent cancer rates in smaller populations, such as neighborhoods near industrial fence lines.

“The cancer rates Denka cited are not specific to the people who have been most exposed to chloroprene,” Terrell said.

Harris, the Denka spokesperson, said the company has “invested over $35 million to reduce its emissions by over 85 percent” since purchasing the facility in 2015 and conducted community air monitoring that showed similar reductions.

The EPA’s letter acknowledged the reduced concentrations, which resulted from an enforcement order from LDEQ. “There is no question, however,” the EPA wrote, “that elevated cancer risk for residents of all ages and school children still exists and has existed as a result of breathing air polluted with chloroprene and that this risk has impacted and currently impacts Black residents disproportionately.”

Taylor, the community advocate, said the letter indicates the agency is “considering our humanity” and “doing what we consider is the right thing.” For too long, he said, residents have operated under the assumption that “our government has abandoned us — we are just sacrifice zones.”

A lifelong resident of St. John the Baptist Parish, Taylor recalled how his children used to run into the house to escape fumes that made their chests hurt. He lives five blocks from the Denka plant, close enough to hear announcements from the company’s loudspeakers. He has grandkids and great-grandkids who attended local schools, including a Catholic school next door to Fifth Ward Elementary.

The EPA letter is a response to civil rights complaints filed on behalf of Taylor’s organization, the Sierra Club and other groups. The complaints cite Title VI of the 1964 Civil Rights Act, which bans the federal government from funding state agencies whose policies or actions discriminate based on race.

The act prohibits both intentional discrimination and disparate impact regardless of intent, said Deena Tumeh, an associate attorney at Earthjustice who helped file the complaints for Taylor’s group. The EPA’s letter noted that 93% of the residents within a mile of the Denka plant are Black, and the Formosa plant is slated for a census tract where 90% of the population is Black, compared to 50% in the overall parish. These demographic patterns can be traced back to the Reconstruction era, the letter said, as freed Black families were able to purchase small parcels of land near plantations. Over time, the plantations were replaced by large petrochemical facilities, while the descendants of those families continued to live in rural, unincorporated towns that became “fence line” communities.

Last month, a judge blocked progress on the Formosa plant by withdrawing its air permits. The judge’s decision cited the fact that state regulators failed to assess cumulative impacts from multiple sources, even though the location suffers from significant existing toxic air pollution that would be exacerbated by the proposed facility’s emissions. LDEQ has appealed the decision. Formosa didn’t respond to a request for comment.

“For years, Title VI letters went to a closet and died,” but this EPA is talking to people and investigating seriously, said Darryl Malek-Wiley, a senior organizing representative at the Sierra Club.

Malek-Wiley, who helped popularize the term “Cancer Alley” in the 1980s, said the real test of the EPA’s dedication to equity will come once it negotiates specific terms with the two Louisiana agencies. Tumeh said the agreement could include the recommendations from the EPA’s letter, as well as additional requirements. That process could take months.