Will community air monitoring bring ‘Cancer Alley’ cleaner air?

For decades, Bertha Myles has felt aggrieved by the foul odors besetting her home. Sitting on her porch, she recalls the Friday after Thanksgiving in 2006 when her husband died of prostate cancer. She fondly remembers his love for biscuits. Looking across the street, she talks about Joyce, her neighbor, who also died of cancer. Myles reminisces about picking pecans and blackberries with Joyce in the forested patch nearby, “just having a good time over there, walking and talking.”

She mourns the loss of her backyard kitchen garden, which once thrived with peas, okra, turnips, mustard, and collard greens. “You couldn’t raise [the garden] no more because it wouldn’t grow,” says Myles, a 78-year-old retired nurse aide. “It’s got to be what’s in the air.”

Myles lives in Alsen, an unincorporated community at the northern edge of what many people call Cancer Alley, a 137 km stretch along the Mississippi River between New Orleans and Baton Rouge, Louisiana. Packed with more than 150 chemical plants and refineries, this industrial corridor has neighborhoods—predominantly Black and mostly low income—facing some of the highest cancer risks from air toxics in the US. A 2022 study linked cancer rates to toxic air pollution in Louisiana’s most impoverished neighborhoods, including in this industrial corridor.

There are few places in the country “with such a concentration of people in close proximity to large industrial pollution sources,” says Larry Starfield, former principal deputy assistant administrator at the US Environmental Protection Agency’s office of enforcement and compliance.

Myles lives next to an infamous landfill, and within 10 km of her home is a Formosa Plastics polyvinyl chloride (PVC) plant that has been cited multiple times for “high priority” violations of the Clean Air Act, ExxonMobil chemical and polyolefin plants, and other chemical and waste disposal facilities. These plants emit vinyl chloride, chloroprene, 1,2-dichloroethane, benzene, acetaldehyde, and other known or suspected carcinogens, as well as pollutants that can cause respiratory illnesses and other health problems.

The EPA’s analyses suggest that, depending on atmospheric conditions, such pollutants can be found at potentially concerning levels up to roughly 50 km from their sources.

In November, on a mild but somewhat humid evening, Myles and about a dozen Alsen residents gathered to discuss a potential path to safeguard their health. They were meeting with Marylee Orr, cofounder of the Baton Rouge–based nonprofit Louisiana Environmental Action Network (LEAN), and Slawomir Lomnicki, an environmental chemist at Louisiana State University. The community has long known LEAN because of its efforts, along with those of other nonprofits, to address environmental problems in the state. With Lomnicki’s help, the organization had begun monitoring the air in four communities along the industrial stretch, including Alsen.

In a landscape where criticisms continue to surface over inadequate air monitoring and regulatory enforcement by the state, LEAN “aims to expand air quality data and air quality literacy,” Orr told the group. “That’s what we’re here to share.”

Lomnicki walked attendees through LEAN’s online portal allowing anyone to access the air quality data, as well as weekly reports he prepares for communities. But these reports come with a disclaimer: the data in them may not be used to allege violations or noncompliance with federal or state law.

A high hurdle confronted by LEAN and other nonprofits and research groups doing similar work in the region is the 2024 Louisiana Community Air Monitoring Reliability Act. The law—which a federal lawsuit seeks to overturn—restricts the use of lower-cost and research-grade sensors to assert pollution violations and limits this power to the EPA’s reference monitors and methods. It also potentially threatens steep fines for breach and limits publicly sharing data obtained from such air monitoring efforts.

But federally approved regulatory air monitors can cost thousands of dollars—an unaffordable price for nonprofits that are already struggling financially to undertake community air monitoring work. Last year, the Donald J. Trump administration canceled or paused billions of dollars in climate and environmental justice grants—including several involving air quality monitoring—deeming the work “radical” and “woke.”

While data from low-cost sensors aren’t always accurate enough to inform regulatory decisions, they could help identify problem areas for more precise monitoring, says Kimberly Tyrrell, a visiting scientist at the nonprofit Environmental Integrity Project.

LEAN wants to use its data to help communities work directly with local industries to seek solutions. “If you feel that it [the pollution] is coming from a certain facility, and it’s coming frequently, and you have a problem with it, we can help you set up a meeting with that facility,” Orr said at the November event.

Some industry officials agree that using data and dialogue to address issues may be a good approach. “When there are good faith efforts . . . you’ll find that industry has been supportive of those efforts,” says David Cresson, president of the Louisiana Chemical Association, which represents dozens of the state’s chemical manufacturers.

But several community members are skeptical about engaging with industry. They say their concerns are often not taken seriously or are even dismissed.

Going forward, LEAN and other nonprofits face two key questions: how to best serve communities and better monitor the air in the region.

While industry pushes to scale up, groups in St. James Parish are seeking a moratorium on any new construction or expansion of petrochemical plants near their neighborhoods along this industrial corridor. Meanwhile, the Trump administration continues to weaken environmental rules.

“Without the EPA being an aggressive enforcer, and without the state having the capacity to put monitors in all these places and follow up, it falls to the communities to try to do what they can,” says Starfield, who advises LEAN on its air monitoring work. But it remains to be seen how and to what extent community air monitoring will empower residents to advocate for cleaner air in Cancer Alley.

Gaps in air monitoring

The rapid establishment of Louisiana’s industrial corridor began in the mid-20th century, when chemical and petroleum companies bought up large, contiguous land parcels—formerly sugar plantations worked by enslaved people—along the Lower Mississippi River. Free Black settlements near the former plantations increasingly became fenceline communities. Their industry-adjacent neighborhoods experienced heightened levels of toxic pollution and chilling health threats.

Such toxic emissions have largely been declining, but persistent localized pollution in industrial clusters remains a concern.

The Louisiana Department of Environmental Quality (LDEQ) conducts continuous air monitoring at about a dozen sites along this industrial stretch. These stationary monitors measure pollutants including ozone, nitrogen dioxide, sulfur dioxide, and PM_2.5. The area also has a few noncontinuous samplers with filters that collect lead and particulate matter, which are sent to a laboratory for mass and composition analyses.

Additionally, the LDEQ uses stainless steel vessels called summa canisters to collect 24 h air samples at limited locations every 6 days. Using gas chromatography/mass spectrometry (GC/MS) and flame ionization detection, lab technicians analyze and quantify around 60 VOCs, including hazardous air pollutants known to cause cancer and other serious health impacts. (The Clean Air Act lists 188 hazardous air pollutants regulated by the EPA.)

The agency may also deploy these canisters for shorter periods, such as when continuous air monitoring indicates that VOC levels exceed predetermined values. In addition, the LDEQ may set up a stationary monitor in “areas of interest for approximately one year” to investigate emerging air quality concerns. After environmental emergencies such as fires, chemical spills, and leaks, the LDEQ brings out a mobile air monitoring van equipped with three GC/MS units, as well as flame ionization and pulsed flame photometric detectors.

But the agency’s efforts are insufficient to capture the true extent of pollution in the region, says Corinne Gibb, a chemist and air monitoring coordinator at the environmental health and justice nonprofit Louisiana Bucket Brigade. Some rapidly industrializing hubs—such as the Donaldsonville area, home to the world’s largest ammonia production facility—lack continuous air monitoring. The LDEQ monitors are also generally not in areas with populations facing the highest health risks, such as fenceline communities, Gibb adds.

Gibb also points out that several monitors measure only two to three pollutants. For instance, the monitor in Ascension Parish doesn’t measure PM_2.5—fine, inhalable particles that can travel deep into the lungs and enter the bloodstream, and that have been linked to cardiovascular and respiratory diseases and adverse birth outcomes.

There are also key hazardous pollutants, such as ethylene oxide, that LDEQ hasn’t tracked. This highly reactive, colorless gas is used to sterilize medical equipment and to make products including plastics, polyester, adhesives, and detergents.

Ethylene oxide is known to be a carcinogen, and regular exposure can increase the risk of certain cancers, including lymphoma, leukemia, and breast cancer. A recent study identified it as the largest contributor to cancer risk in parts of the corridor.

But accurately measuring ethylene oxide can be a challenge for many instruments, particularly at the extremely low levels (PDF) at which it starts to pose health risks. Without monitoring data, the next best option is a model, says Lauren Padilla, a senior environmental data scientist at the Environmental Defense Fund, an advocacy group.

The EPA has developed models that estimate concentrations of ethylene oxide and other toxic air pollutants, as well as their associated health risks, across the US. These models use air monitoring data submitted by state, local, and Tribal air agencies, as well as yearly toxic emission estimates that many industrial facilities are required to self-report. It’s pretty much an honor system, Padilla says.

Although the EPA performs quality checks on these self-reported data, recent studies have found that ground-level measurements of several hazardous air pollutants can be a lot higher than the model calculations.

Using state-of-the-art instrumentation, a Johns Hopkins University–led month-long, mobile air monitoring study revealed median and maximum ethylene oxide concentrations of 27.7 parts per trillion (ppt) and 57.2 ppt at the census tract level in the middle section of Louisiana’s industrial corridor compared with 2.6 ppt and 7.8 ppt estimated by the EPA’s air toxics screening assessment (AirToxScreen) model for the same area. In a follow-up study, the team included measurements of 17 carcinogenic VOCs, including ethylene oxide, chloroprene, and formaldehyde, and found that its estimates of cancer risks in this region were up to 11.6 times as high as the EPA’s. (The agency didn’t answer C&EN’s questions about these risk differences.)

“Without having on-the-ground measurements, you’re kind of flying blind and assuming that what’s out there is sufficient to make decisions about building a [new] facility or what populations are exposed to,” says Peter DeCarlo, a study coauthor and an environmental health and engineering scientist at Johns Hopkins.

In 2024, the EPA announced fenceline monitoring requirements for more than 200 chemical companies nationwide that use, store, or emit ethylene oxide, chloroprene, benzene, 1,3-butadiene, ethylene dichloride, and vinyl chloride. But 2-year, renewable exemptions granted to dozens of facilities by the Trump administration will delay monitoring that was slated to begin this summer. Fenceline monitoring for benzene at the perimeter of petroleum refineries required by a 2015 rule remains intact.

“People deserve to know [what they’re breathing]; they have the right to know,” Gibb says. “It’s simple.”

Taking charge of monitoring the air

In 2022, the EPA announced the largest investment in community air monitoring in the agency’s history. It allocated $53.4 million for 132 projects across the country, including 4 in Louisiana, that would focus on communities “underserved, historically marginalized, and overburdened by pollution.” For grantees and other interested nonexperts, the EPA held a five-part webinar series on developing air monitoring objectives and plans, selecting equipment and locations, quality control, data analyses, and communication.

“Historically, monitoring was done by government entities,” Chet Wayland, then director of the EPA’s Air Quality Assessment division, said during one of the webinars. But with more-advanced and lower-cost technologies, “we’re seeing a huge surge in the abilities of communities to do monitoring and gather their own information,” he said. “That’s a game changer.” For the agency, this was a way to help address gaps in air quality information in underserved regions.

LEAN, one of the recipients of EPA funding, began its project in December 2023. In the first phase, the organization hired the climate technology firm Aclima to operate specialized mobile vehicles along Louisiana’s industrial corridor and measure and map pollutants. They included carbon dioxide, PM_2.5, ozone, methane, nitrogen dioxide, total VOCs (TVOCs), and BTEX (benzene, toluene, ethylbenzene, and xylene). Running until March 2024, the vehicles traversed multiple routes at various times of day and revealed 29 pollution hot spots.

During the second phase, LEAN rented four stationary monitors to continuously measure some of those pollutants in communities that were open to partnering with it. After calibration, the monitors have been running nonstop since September 2025—providing nearly real-time data to residents living close to pollution hot spots. LEAN makes these data, averaged over 15 min, available via the portal hosted on its website.

In his weekly reports for the community, LSU’s Lomnicki highlights levels and times of day when pollutants such as PM_2.5 and nitrogen dioxide exceed national ambient air quality standards. He provides details about the direction of the wind that transported these pollutants—information that could potentially allude to their sources. Lomnicki flags one “big limitation”: the monitors measure TVOCs but don’t identify which VOC species are being captured and in what amounts—unlike the Johns Hopkins’s study.

In Geismar, an unincorporated community at the heart of the industrial corridor, Lomnicki has observed sustained, elevated PM_2.5 levels, for instance. Wind direction data suggest that some of these emissions, which he says are concerning, are coming from industry. And while the levels may not always surpass national air quality standards, frequent occurrence could have serious health implications, Lomnicki says.

Nearly 20 years ago, “I almost bought a house in Geismar,” Lomnicki says. “And now, when I look at these data, I’m so lucky I didn’t.”

For Geismar resident Malaika Favorite, the hope is that these data may provide “proof” that her community is exposed to industrial pollution, “as opposed to just saying we think or we believe.”

The Louisiana Bucket Brigade has also installed two air monitors in the Donaldsonville area that measure particulate matter, including PM_2.5, as well as ammonia and nitrogen dioxide. And since last June, the Environmental Defense Fund, in collaboration with the nonprofit Deep South Center for Environmental Justice, has been deploying 15–20 AirPen monitors in the industrial corridor as part of 3–4 week campaigns. The sorbent tubes in these monitors are swapped weekly and sent to Colorado State University to track 17 top hazardous air pollutants.

Woman with short gray hair, wearing glasses and a green T-shirt, uses a screwdriver to work on a blue panel attached to a metal pole.

Woman wearing sunglasses and a printed top stands in front of an air monitor that’s fixed to a T-pole.

But there’s an important next step that community air monitoring projects need to consider. “Even if we have reliable data, even if we set a project up well, even if we can understand the causes of bad air quality, what are we going to do about it?” asks Tyrrell at the Environmental Integrity Project.

Path to cleaner air?

Will such data drive change, how long will that take, and what will those changes look like are open questions. Recent history demonstrates that even with gold standard regulatory air monitoring data, action can be slow.

Take the case of Denka Performance Elastomer’s neoprene plant near LaPlace, Louisiana. In 2015, the EPA’s model assessments flagged a census tract next to the plant for having the nation’s highest cancer risks from toxic air pollution. Driven largely by chloroprene emissions from the facility, Denka and the EPA set up an air monitoring plan in 2016. Over the years, EPA-approved fenceline monitors revealed long-term chloroprene concentrations up to 14 times as high as the agency’s acceptable level of 0.2 µg/m³. This was despite Denka installing pollution control equipment and slashing emissions by 85%.

The EPA and US Department of Justice filed a lawsuit in 2023 to compel Denka to further reduce chloroprene emissions. In 2024, the company grappled with a 90-day deadline to slash emissions; it suspended operations in May 2025, citing the high costs of pollution control.

“Over 8 years, they had the data and still it takes so long for anything to be done,” says Lydia Gerard, 71, a member of the community advocacy group Concerned Citizens of St. John, who lives near the Denka plant and whose husband died of kidney cancer in 2018.

Meanwhile, LEAN wants to use the air quality data it obtains with lower-cost sensors not only to keep communities informed of pollution levels but also to help them start a dialogue with industries when concerns arise. “In current times, there’s been more movement and positive reception in dealing with the industry directly than there is in dealing with the government,” says Michael Orr, LEAN’s communications director and Marylee’s son. “There are like-minded people inside those organizations who are willing to have those conversations.”

For example, International-Matex Tank Terminals (IMTT), a New Orleans–based company that specializes in the handling and storage of bulk liquid products, including chemicals, announced a partnership with LEAN last September to establish four air monitors in the neighboring community of St. Rose, Louisiana. Spurred by residents’ concerns about odors, IMTT wanted to understand the odors’ origin and “fix it, if there’s anything on our side,” says CEO Carlin Conner.

In January, Lomnicki noticed many days with sustained, elevated TVOC levels logged by the monitors, whose data are also publicly displayed on LEAN’s website. The levels peaked at about 350 ppb and lasted for several hours, although they didn’t elicit odor complaints. LDEQ doesn’t typically conduct additional sampling unless concentrations remain at or exceed 1,000 ppb for 10 min.”

“We know it’s perfectly acceptable from a regulatory point of view,” Conner says. “We need to understand what’s happening when those spikes happen so we can see if there is a way to mitigate [them].”

So far, IMTT says it hasn’t been able to identify any specific activity within its facility that may have contributed to the increases in TVOC levels. And while technicians are still trying to trace what happened, the company is developing a protocol so that the next time such elevated levels appear, “we’re going to be better prepared,” Conner says. IMTT also plans to work with an independent toxicologist and public health expert to assess impacts associated with pollution the monitors capture.

But the incident poses a larger question about what kind of pollution increases will spur action from industry and how much sway community air monitoring data can have outside regulatory frameworks. For LEAN’s Marylee Orr, the aim is to stop “smaller issues from becoming a bigger issue.” She adds, “most [industry] managers I speak with, they want to resolve that problem.”

Still, agreements between industry and community groups are voluntary, and not all companies may be inclined to engage in them.

The PVC manufacturer Shintech, for instance, is unlikely to invest in an IMTT-like collaboration with LEAN, at least in the near term. The company is seeking a 2-year emissions waiver from the Trump administration and is waiting to see what EPA regulatory requirements—including fenceline monitoring—it will be subject to.

“Until we understand that clearly, I don’t think we’re going to do anything significantly more outside of our complex,” says Danny Cedotal, vice president of manufacturing at Shintech. He maintains that investing in air monitoring “as close to the source as possible” can flag issues immediately versus monitors placed in communities 2km or so away.

Meanwhile, Favorite, the Geismar resident, is skeptical about community-industry dialogue as the main approach to resolving air quality concerns. Even if residents have information about the air quality in their neighborhood, “What can we do?” she asks. “We’ll just complain, and they [industry officials] will say, ‘Oh, it’s not true.’”

Quisha Reed-Jones, executive director of a local organization called Alsen St. Irma Lee Community Village, shares Favorite’s skepticism. While Reed-Jones appreciates LEAN’s efforts and quick access to its data, she feels that industry doesn’t take community concerns about pollution and health seriously.

But like many other residents, Reed-Jones also doesn’t have a lot of faith in the LDEQ to help communities navigate air quality concerns. As Sharon Lavigne, an environmental justice activist and founder of the advocacy group Rise St. James, says, “They’re not on the side of the people. They’re not going to accept the [community air monitoring] data.”

During a 2022 high-profile civil rights investigation, which the government later dropped, the EPA found significant evidence suggesting that the “actions or inactions” (PDF) of LDEQ and the Louisiana Department of Health had continued to cause disproportionate harm to Black residents living in the state’s industrial corridor.

‘This is our home’

Many chemical companies are still seeking to build in already overburdened parts of this region. In St. James Parish, for instance, Formosa Plastics has purchased 2,400 acres to build a proposed $9.4 billion petrochemical complex. A 2019 ProPublica analysis indicated that the facility could triple the levels of cancer-causing pollutants that fenceline communities are exposed to.

As part of a roughly $4 billion joint venture in Ascension Parish, the fertilizer giant CF Industries is aiming to construct the world’s largest low-carbon ammonia plant. And in Iberville Parish, Shintech recently announced a $3.4 billion expansion to increase production of the PVC raw materials chlor-alkali, ethylene, and vinyl chloride.

Communities are voicing opposition and suing over permits. “How many of our neighbors have to die?” RISE St. James’s Lavigne asks in a statement.

At an LDEQ air permit hearing in November for the proposed CF plant, 23 attendees opposed the permit approval and 13 spoke in favor. CF operations manager Terry Dugas touted the project’s ability to “advance the clean energy industry and global decarbonization efforts” and “create thousands of construction jobs, along with [103] high-paying permanent jobs.”

On the other hand, community group representatives expressed concerns that the facility would release toxic pollutants, including ammonia, and carcinogens such as formaldehyde. Other people questioned whether locals would even get many of those heralded jobs. They asked if LDEQ had already decided to approve CF’s permits and whether the hearing was a mere formality.

Residents of Modeste, an unincorporated village, who stand to be affected, delivered moving statements. Mekaylyn Lavigne, 20-year-old granddaughter of Sharon Lavigne, is among the fourth of five generations to live on a roughly 15-acre property nestled between sugarcane fields along Louisiana Highway 405. Growing up alongside extended family, caring for rescue dogs and feral cats—and the occasional rooster from the neighbor’s farm—is a quiet, rural way of life she isn’t willing to trade. But being surrounded by more toxic pollution shouldn’t be their only alternative, she says. Lavigne and many others in the area refuse to move as another industry giant, Hyundai Steel, wants to buy and build a $5.8 billion steel mill on their land.

A woman in a blue shirt sits at a table behind two large framed photos.

Woman wearing dark trousers and a blue shirt stands with a small dog, with a gray house and a tree in the background.

For Twila Collins, whose front yard is dotted with “not for sale” signs, putting the Modeste community in harm’s way is unacceptable. The 55-year-old lost her mother to cancer and her 9-year-old son to an asthma attack, and she has undergone surgery for colon cancer. But memories of her loved ones are still alive in her ancestral home. “You can’t replace that,” Collins says. “This is our home, that’s paid for, that we shouldn’t have to give up.”

The Louisiana Bucket Brigade installed an air monitor on Collins’s property to capture pollution in her neighborhood and help the community assess the air quality. The organization also wants to use the information to put pressure on industries that want to expand further in the region. While there are many hazardous pollutants that her organization’s monitors don’t track, Gibb thinks the information is important to create awareness and supplement air monitoring efforts by other nonprofits and research groups.

Back in Alsen, Myles ponders what will come of all the ongoing efforts to gather data. “What do you do with it? Where do you go from there?” she asks. Her hope is clean air, someday.

CORRECTIONS

This story was updated on April 10, 2026, to correctly spell the names of two Louisiana residents. They are Corinne, not Corrine, Gibb, and Loraine, not Lorraine, Thompson. In addition, Mekaylyn Lavigne is Sharon Lavigne’s granddaughter, not niece. And because of a technical error, this line was was missing from the story and has been added: “LDEQ doesn’t typically conduct additional sampling unless concentrations remain at or exceed 1,000 ppb for 10 min.”

Priyanka Runwal is an associate editor and an award-winning environment and health reporter at C&EN.

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