LaPlace, Louisiana (CNN) Geraldine Watkins sits at the kitchen table in her ranch home, rattling off the names of friends and relatives in her small Louisiana town who've died of cancer over the last 40 years.

Her grandchildren suffer an array of ailments, from skin conditions to breathing problems. Her 7-year-old great-grandson's breathing is so labored, she says, "you can feel his heart trying to jump out of his chest."

Watkins lives in the shadow of a plant that spews chloroprene -- a chemical so toxic the Environmental Protection Agency says nearby residents face the highest risk in the country of developing cancer from air toxins.

"You gotta live here to try to breathe the air, drink the water, see the children so sick and watch people die," Watkins says. "Industry is wonderful to have, but if it's killing the people in the area that they live in, what good is industry?"

Watkins is a worthy advocate, a 76-year-old great-grandmother challenging those in power. Her words are often punctuated by folksy aphorisms: "Nothing beats a failure but a try," she says.

And try she will.

A town wants answers

The town of LaPlace, Louisiana, lies along the Mississippi River, a stone's throw from Lake Pontchartrain and the Maurepas Swamp. It sits in the heart of an area that's become known by locals as "Cancer Alley," a vast industrial stretch between New Orleans and Baton Rouge where dozens of petrochemical plants dot the landscape.

One sign posted by a local advocacy group warns the town's 29,000 residents that they are "more likely to get cancer due to chloroprene air emissions." The warning refers to the Denka Performance Elastomer plant at the edge of town, where a vast network of pipes and valves stand testament to industry.

The facility looms over Fifth Ward Elementary School, where children run around the playground oblivious to the toxic emissions in the air.

The Denka plant is the nation's sole producer of neoprene, the synthetic rubber used in everything from wetsuits to automotive hoses. It's also at the center of a battle over its emissions.

The plant, formerly operated by DuPont, employs more than 200 workers and has been in this spot for nearly 50 years. The facility plays a vital manufacturing role as the nation's only producer of neoprene, a synthetic rubber that's found in everything from gaskets and hoses to fishing waders and wetsuits. But it also emits 99% of the nation's chloroprene pollution, according to the EPA . Chloroprene is the main chemical used in the production of neoprene.

In 2010, the EPA determined that chloroprene is "likely carcinogenic to humans," meaning studies showed it likely causes cancer in people. The EPA has not set a legal limit for chloroprene emissions. But according to a May 2016 memo, federal regulators said the "upper limit of acceptability" for cancer risk was an annual average of 0.2 micrograms of chloroprene per cubic meter. Anything more than that would increase the risk of developing cancer, the EPA determined.

Residents say they were largely unaware of the 2010 EPA finding. But in December 2015, the EPA updated its National Air Toxics Assessment map, which showed an elevated risk of cancer around the plant -- prompting Denka to enter into an agreement with the state of Louisiana to voluntarily reduce chloroprene emissions by 85%

Tensions in the community mounted after Denka representatives and state environmental officials briefed the public on the agreement.

The town hall meetings may have been intended to reassure residents, but they only seemed to create more questions: Residents wondered why they weren't warned years before and said their complaints have been ignored.

While Denka agreed to the voluntary 85% reduction, it disputes the EPA's 0.2 recommendation and insists its own research shows no connection between chloroprene and cancer. Denka is a Japanese chemical company that bought the plant from DuPont in 2015.

Denka officials say the EPA based its cancer estimate on faulty science and have demanded that the EPA issue a correction. The company commissioned and submitted a study that argued chloroprene's classification should be changed from "likely carcinogenic to humans" to "possibly carcinogenic" -- and that the 0.2 guideline should be changed to 31.2, more than 150 times the EPA's recommendation.

An EPA spokesman told CNN the agency is reviewing the company's complaint but indicated the science behind the agency's findings was solid.

In the spring of 2016, the EPA installed six canisters near the plant -- including at the hospital, levee and two local schools -- to collect air samples. Every three days, the air quality is tested. The daily readings have been jarring -- 10 times, 50 times and 100 times the EPA's "upper limit of acceptability" for cancer risk. On one occasion last November, the reading spiked at the levee and tested 700 times the recommended cancer risk, according the EPA data.

At the elementary school, the average concentration from May 2016 to August 2017 was more than 34 times the EPA's recommendation.

"Our primary concern is with exposures over a lifetime," the EPA's spokesman wrote CNN in an email. "If the concentrations were to persist at current levels for a lifetime, there is potential for adverse health effects. This is why EPA and the state are working with Denka to reduce emissions."

Residents aren't satisfied with the 85% solution. They've rallied together to form the Concerned Citizens of St. John the Baptist Parish. Many wear T-shirts that read: "Only 0.2 will do."

In June, 13 residents filed a class-action lawsuit against the plant, aimed at forcing the company to reduce emissions to meet the 0.2 EPA risk recommendation.

Pollution from the facility, the suit alleges, is "sufficient to cause physical discomfort and annoyance to plaintiffs, who must often confine themselves indoors to escape the excess concentration of chloroprene emission."

"In addition, the excess concentrations of chloroprene emissions lead to a reasonable and justified fear of cancer," the suit says.

Plant manager: There is no cancer risk

Sitting inside the facility, Denka plant manager Jorge Lavastida said the company is sensitive to the concerns of residents about air quality. "We want to be a part of this community. We want to be admired by this community. We want to have employees from this community," he told CNN.

But he disputed the EPA on almost every point, citing the plant's own study and emphasizing the company voluntarily committed to the 85% emissions reduction plan at a cost of nearly $18 million.

"It's our No. 1 priority," he said.

The company has already finished two of the four projects included in the reduction plan. He said the company hopes to complete the other two by year's end, although the work is months behind due to unexpected complications. "We are fully committed and fully resourced to the projects," he said.

Denka plant manager Jorge Lavastida says the company doesn't believe chloroprene causes cancer, but it committed to a plan to reduce emissions by 85%.

Citing the company's own study, Lavastida added this about the safety of the chloroprene being emitted: "There is no relationship between chloroprene and cancer."

Asked if that means the company believes chloroprene does not cause cancer, he said simply, "That is correct."

He added he is "optimistic" the EPA will revise its 0.2 guideline soon.

Lavastida said one of the projects already completed has reduced chloroprene emissions by 62%. "We know they're working," he said. The company maintains six air quality monitors of its own in and around the plant, separate from the EPA's.

However, EPA data provided by the state to CNN showed something completely different: The air quality has worsened, not improved, at five of the six government testing sites over the last year.

Asked about those readings, Lavistida said, "I don't know if I can explain that."

Short-term health effects of being exposed to high doses of chloroprene range from headaches and hair loss to irritability and a rapid heartbeat, according to the EPA. It may also affect the liver, lungs, kidneys and the immune system.

Long-term exposure can lead to respiratory problems, skin issues, chest pains and neurological problems, in addition to an increased likelihood of cancer, the EPA says.

Statewide cancer rates are not specific enough to capture whether the incidence is higher in the areas around the plant. That's because cancer rates are calculated for entire parishes, not at a more local level.

The current data for the parish doesn't show a higher rate of cancer among the parish's 44,000 residents; in fact, it has one of the lowest rates in the state -- a figure that company and state officials use to defend their efforts.

But more precise data may soon be available. A new state law requires the Louisiana Tumor Registry to track cancer cases by ZIP codes and census tracts to help determine whether certain areas within parishes are more prone to cancer.

'Filling us up with poison'

Robert Taylor III grew up near the plant and was in and out of the hospital with kidney problems throughout his youth. He moved away after high school and had no problems for more than 20 years.

But six months after moving back, Taylor says, his kidneys failed.

Sitting at his kitchen table, he points across the street: "Husband and wife died from cancer." Then, he waves his hand toward another home: "Husband died of cancer. Both of his sons got cancer."

"These people are filling us up with this poison," he says of the plant.

Long-time resident Robert Taylor has suffered an array of kidney problems since youth. His daughter, Nayve Love, needs an oxygen machine to help breathe several times a week.

Taylor is part of the class-action lawsuit against Denka. He joined on behalf of himself and his daughter, Nayve Love, who suffers breathing problems and needs to use an oxygen machine several times a week.

His father, who founded the Concerned Citizens of St. John the Baptist Parish, is also a plaintiff.

"We're not just going to sit around and let them push us around," Taylor said. "They don't have any compassion for human life. My little girl is 10 years old. She's innocent."

Wilma Subra is a chemist and long-time environmental activist in Louisiana. She's been keeping close tabs on the Denka plant and has helped advise the citizens' group.

She said she's appalled at how state officials have seemingly turned a blind eye to the pollution.

"They have dismissed the issues and concerns of their citizens here in St. John the Baptist Parish," she said. "Meanwhile, the citizens are continuing to breathe the air with chloroprene every single day."

"If we do not continue to push the company to put on (additional) control technologies to reduce the chloroprene levels," she said, "the people will continue to be exposed."

State environmental boss: Ignore EPA figure

Chuck Carr Brown, the secretary of Louisiana's Department of Environmental Quality, says he tries to straddle the line between industry and the people he's committed to serving. His agency's mission, according to its website, is "to promote and protect health, safety and welfare while considering sound policies regarding employment and economic development."

At a heated public meeting last December, he told residents that much of the cancer concerns were overblown and the situation wasn't anything comparable to the lead-contaminated water crisis in Flint, Michigan

"It's not like there's a smoking gun somewhere in St. John Parish," he said.

Brown praised the plant's commitment to reducing emissions by 85% with what he called the "best available control technology."

"We're going to monitor for at least another year, and we should start seeing these numbers start trending downward," he said.

During the meeting, he dismissed the EPA's 0.2 cancer guideline on chloroprene emissions. "That's not a standard," he said. "That's just a guidance."

Adding to the tensions between residents and his agency, Brown called vocal residents around the plant "fear-mongers." In an interview with CNN, he said, "I don't want to repeat that."

"I'm not going to say I regret using the term. I just felt like I could've used a different term," Brown said.

He also expressed frustration that "everybody seems to ignore" data put out by his agency. "At this point, there is no reason to believe that there is any undue risk or exposure to the folks in St. John Parish," Brown said. "If that changes, then we'll be the first ones to take immediate action."

He again dismissed the EPA's 0.2 guideline. "It never was an enforceable standard," he said, "and it's still not an enforceable standard."

He said his agency hopes to use the new technology being installed at the plant to set a standard for chloroprene emissions -- and not be hamstrung by the 0.2 EPA guideline. As head of the state's environmental organization, he said, "I wanted to enter a working relationship with the company in order to install what we call the best available control technology."

"That's why I've tried to tell everyone: Detach yourself from that number and let's work toward a solution that involves the best available control technology."

"But if that's the guidance," CNN asked Brown, "why not be guided by it?"

Brown stood his ground, saying the new technology would be used to set the standard, not the EPA's 0.2 figure. "To artificially target a number that you can't legally enforce," he said, "it actually makes no sense."

He rejected suggestions he was following the company's lead. "That's not what we're doing," he said. "It's not like you just turn a valve or are working with LEGO pieces. We're talking about large piping, large tubing, rerouting and engineering."

CNN asked Brown why tests of the air quality have shown more toxins this year, rather than dropping as he pledged back at the December meeting. "We'll show you some data that refutes that," he said. "You'll get a spike. But when you start looking at the average over a month, it's really trending downward."

His detractors, he said, should look at the data provided by his agency to "see the real facts." He paused and spelled out the word, "F-A-C-T," adding that "everything else is just somebody's theory."

CNN did look at the facts provided by Brown's office after the interview, and it confirmed what we already knew: That the toxicity in the air recorded by the EPA was worse in June 2017 at five of the six testing sites than it was in June 2016 despite the improvements at the plant.

In her humble ranch home a little over a mile from the plant, Geraldine Watkins bites her tongue when told of Brown's comments. She says some words aren't meant to be repeated.

Geraldine Watkins says the plant needs to change its ways: "You gotta live here to try to breathe the air, drink the water, see the children so sick and watch people die."

"My tongue gets blue, but I can control it," she says.

She was at the December meeting when Brown addressed the crowd. His comments back then filled her with rage: "If eyes could kill, I would have cut him to death that night."

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She mulls over Brown's latest remarks, thinking about her great-grandchildren's unexplained conditions.

"This is horrible," says Watkins, who is not part of the class-action suit. "If you don't live in the area, you can say anything and everybody is supposed to believe that."

She wants clean air to breathe, for everyone in town -- and for herself.

"Let me live," she says. "Whatever time I have left, let it be decent."