NEW ORLEANS, La.—For years, environmental groups have called the industrial corridor along the lower Mississippi River between here and Baton Rouge “cancer alley.”

The moniker describes a winding, 130-mile stretch along the river that is dotted with more than 200 industrial facilities including oil refineries, plastics plants, chemical plants and other factories that emit significant amounts of harmful air pollution. The provocative name has drawn unflattering global attention to the state of Louisiana and animated the struggles of Black descendants of enslaved people, many of whom live in close proximity to petrochemical plants that contribute to the insatiable demand for products derived from crude oil or fossil gas, such as gasoline and plastics.

Even though U.S. Environmental Protection Agency mapping shows the region’s residents have some of the highest health risks in the nation from breathing toxic chemicals, state environmental regulators and industry officials have long disputed the term. 

The standard line from public officials has been that the state’s cancer registry shows cancer cases in parishes, or counties, along the industrial  corridor do not exceed statewide averages. Indeed, that was what Louisiana Department of Environmental Quality spokesman Greg Langley said recently when asked what the public should make of the term “cancer alley.”

“LDEQ does not use the term cancer alley,” he said. “That term implies that there is a large geographic area that has higher cancer incidence than the state average. We have not seen higher cancer incidence over large areas of the industrial corridor between Baton Rouge and New Orleans.”

But now, there’s no more room for debate, according to Kimberly Terrell, a research scientist and director of community engagement at the Tulane Environmental Law Clinic. Two studies that she and the law clinic research coordinator Gianna St. Julien have published in peer-reviewed journals in the last 13 months provide more scientific credence to the claim that cancer alley is real, and that state environmental regulators have helped to create it with inequitable application of air quality rules.

The studies come amid ongoing environmental justice battles over new or expanded petrochemical plants, including the massive, $9.4 billion Formosa plastics manufacturing complex proposed for St. James Parish that’s been delayed by the courts, and a promise by the EPA to more closely monitor pollution in the area. 

The EPA has also been investigating whether Louisiana environmental regulators have violated residents’ Civil Rights Act VI protections related to proposed or existing industrial facilities in the area. The Tulane law clinic represents some of the groups that are challenging state regulators.

“Coming into this position a few years ago, what really struck me was that as much dialogue as there has been about cancer alley, there hasn’t been a lot of research,” Terrell said in late January at a briefing organized by the environmental group Beyond Plastics. “Those data gaps benefit polluters and are weaponized against communities.” 

But data gaps are starting to be filled.

In 2018, the Louisiana Tumor Registry began making available to researchers cancer incidence rates at the census tract, or neighborhood, level. Terrell said that change, along with using the EPA toxic air risk estimates, opened a new way of looking at pollution and cancer in the state.

In January 2022, Environmental Research Letters published a study by Terrell and St. Julien that found air pollution was linked to higher cancer rates among Black and impoverished communities.

A second study by the two researchers published last month in the journal Environmental Challenges asked whether Black communities in Louisiana bear a disproportionate share of air pollution risks. The researchers found that industrial emissions in Louisiana are seven to 21 times higher in communities of color compared to white communities, and blamed permitting practices by state regulators for the discrepancy.

In October, as a response to the civil rights complaints, EPA criticized LDEQ and the Louisiana Department of Health in its preliminary findings.

The EPA told state officials there is “significant evidence suggesting that the Departments’ actions or inactions have resulted and continue to result in disparate adverse impacts on Black residents of St. John the Baptist Parish, St. James Parish, and the Industrial Corridor.”

The complaints targeted toxic emissions from Denka Performance Elastomers and other sources in St. John the Baptist Parish, and the proposed Formosa project, which would emit more than 800 tons per year of toxic pollution and put up to 13.6 million tons of greenhouse gases into the atmosphere per year, an amount roughly equivalent to 3.5 coal-fired power plants.

We caught up with Terrell and St. Julien following the environmental briefing to discuss their research and its implications.

This transcript has been edited for length and clarity.

How did cancer alley come to be known as cancer alley?

Gianna St. Julien: The one we’ve heard from some of the clients at the Tulane Environmental Law Clinic would be that, in the 1980s, the Oil, Chemical and Atomic Workers Union had been actively fighting a company. As protests weren’t working to get that company’s attention, they planned a meeting or were brainstorming alongside community members. Two of the organizers present, Darryl Malek-Wiley, who actually works for Sierra Club, and (union activist) Richard Miller were throwing (ideas) around and eventually came up with the term cancer alley. And it went a little further than that. A person who was a part of the union, who had a lot of land along the Mississippi River, put up a billboard that said, “Welcome to Cancer Alley,” and that name kind of stuck.

What do the Tulane Environmental Law Clinic clients tell you about what it’s like to live near petrochemical plants in the area known as cancer alley?

St. Julien: We hear that there are constant diagnoses, whether it’s family members or neighbors, of cancer and other diseases. These are people who are living there for their entire lives. Long-term exposures to all of these toxic air pollutants that are emitted by these facilities, over time, are going to have these different health effects. 

Up until the research that y’all did on air pollution and cancer that was published last year, was the label “cancer alley” based on any particular science?

Kimberly Terrell: It depends on how you define cancer alley. I define it as industrialized communities in Louisiana, where people are burdened with high cancer risk from pollution exposure. And under that definition, absolutely, yes, there was scientific support for that. And that support was in the form of the EPA’s National Air Toxics Assessment. Communities (are) concerned about the places where pollution is happening, and the health outcomes in those places. And we know that severely polluted neighborhoods are really common in Southeast Louisiana, but they’re also common in Southwest Louisiana and in other parts of the state. And so when we consider those communities collectively to represent cancer alley, absolutely, we know that pollution is having an impact.

What motivated you to try to bring clarity to this issue?

St. Julien: We have clients that are represented by the clinic, telling us these firsthand experiences. And often the burden of proof is placed on the communities to try to prove what’s going on there. So we wanted to look at the science and see if it actually supported their claims.

In 2018, the Louisiana tumor registry began publishing annual cancer numbers for census tracts. What was the significance of that?

Terrell: Prior to that, it was hard to really understand what was going on, on a neighborhood scale. Once the tumor registry did start to release that data, in 2018, we were able to have much larger sample sizes (and) compare (the cancer data) with all of the other environmental data that we had been collecting. Once we had the census tract level data, we were actually able to break things down a lot smaller, and really look at things from that neighborhood level.

What did your research on pollution and cancer reveal? 

Terrell: We found that severely polluted, predominantly Black neighborhoods in Louisiana have abnormally high numbers of cancer cases. And when I say abnormally high, I mean, accounting for the demographics, accounting for the poverty status of that neighborhood. And so the data really demonstrate that pollution exposure is one of multiple reasons why Louisiana has one of the highest cancer rates in the U.S.

How definitive was it in terms of pinning the cancers on pollution as opposed to cigarette smoking or diet or that sort of thing?

Terrell: We can’t say which cancers came from pollution versus other factors. But we can say there are a certain number of extra cancer cases that are attributable to pollution. And so looking at the entire decade that was represented in our study, that number is 850 extra cancer cases. It’s important to keep in mind that we’re talking about severely polluted communities, and we’re also not talking about all the other health outcomes. So if a person dies of COPD from pollution exposure, they might not have had the opportunity to develop cancer. We focus on cancer a lot, because that’s what we have the best dataset for. There is no other disease registry in Louisiana, with publicly available data, except for cancer.

How many people live in the area known as cancer alley?

Terrell: In our cancer study, where we looked at neighborhoods across Louisiana that were severely polluted and disproportionately poor, the total population was just over 400,000. So that’s about one-tenth of the state’s population.

How are these findings significant?

Terrell: They are a useful tool in community advocacy to support the firsthand knowledge that communities are sharing with decision-makers. It should be enough to provide that firsthand experience. But for better or worse, decision-makers often want to see data. And they often want to see Louisiana-specific studies. We have decades of nationwide research demonstrating that Americans who are exposed to higher levels of pollution die sooner, develop lung cancer or develop other health problems. There’s no reason to think that people in Louisiana are different. But having a Louisiana-focused study can be a really powerful tool.

This was the first study of its kind in Louisiana, correct?

Terrell: Yes, it was the first study to look at the entire state and to actually measure pollution. There’s literally been, I think, three studies published in the peer-reviewed literature related to pollution and cancer in Louisiana.

You had another study that came out in January this year, which  found that industrial permitting by state regulators drives Louisiana’s pollution disparity. What was the question that you were seeking to answer there? 

Terrell: We wanted first to quantify the pollution disparity. Based on everything we see in front of us, it’s pretty clear that communities of color have higher pollution burdens in our state, but we wanted to know how much higher and, importantly, we wanted to know if that disparity could be explained by industrial infrastructure. Because that’s what we’ve heard, both from journalists and from the Louisiana Department of Environmental Quality. The LDEQ recently formally responded to allegations of discriminatory air permitting by claiming that it was infrastructure that drives where plants are located. 

What were your conclusions?

Terrell: We found that, depending on the pollutant, you’re talking about communities of color with industrial facilities having seven to 21 times higher emissions compared to white communities with industrial activity. So I really want to emphasize this is an apples-to-apples comparison. We’re only comparing neighborhoods where you have industrial operations. So yes, industry clusters around infrastructure. But that doesn’t explain why it clusters in predominantly black neighborhoods within that group of neighborhoods that have infrastructure.

How do you hope your research will affect the larger dialogue over environmental justice in the region?

St. Julien: It’s very clear that there is an issue in Louisiana that’s been going on for a very long time where industry targets these predominantly Black, impoverished communities. There are examples nationwide, in previous studies where work like this has resulted in more strict standards as far as what these facilities can emit. Louisiana is a bit behind, and there is a bit of catching up to do. We’re already heavily industrialized, but there are more facilities that are trying to make their way into Louisiana. Ultimately, it comes down to protecting the health of people living within the state that are currently being overburdened and don’t exactly have access to resources to protect their health.

I guess it boils down to what science can bring to the discussion.

Terrell: I’m hopeful that these studies will result in better use of science in decision-making. We know right now that science is often ignored, or data are misconstrued. I’m hopeful that having these studies available for community members to cite elevates the conversation to where we’re talking about facts and data and statistics. I’m really hopeful that LDEQ in the near future will acknowledge that we have a pollution disparity in Louisiana because it’s surprising that we are not even at that point.