Residents in the town of Reserve, Louisiana have been diagnosed with cancer at “highly unusual” rates, according to a new academic study, which is set to further embolden local residents in their fight against toxic emissions from a nearby chemical factory.

The report, released Wednesday by the University Network for Human Rights (UNHR), provides residents with the most detailed and comprehensive evidence to date that they are at an especially pronounced risk of cancer and other negative health effects due to toxic chemicals in the air.

Reserve is the focus of a year-long Guardian series, Cancer Town, chronicling the fight for clean air in the predominantly black town, as well as other communities in the area between New Orleans and Baton Rouge, often referred to as Cancer Alley due to a concentration of toxic pollution from petrochemical factories.

The toxic emissions in Reserve, a town in St John the Baptist parish, primarily come from the Pontchartrain Works facility, the only place in America to manufacture the synthetic rubber neoprene. The US government considers chloroprene, the primary constituent of neoprene, as likely to be carcinogenic to humans.

Researchers found that 10.5% of survey respondents in the area immediately surrounding the plant had experienced a cancer diagnosis – even when they removed households with frequent cigarette smokers from the analysis – a rate they describe as “extremely improbable”.

The report determined that a typical US population made up of the same race, sex and age composition as the one surveyed would experience an average diagnosis rate of 7%, and the likelihood of it being as high as it is simply by chance is a minuscule 0.37%.

“The findings are disturbing, and they highlight that there is need for much more study of the health status of people living in Cancer Alley,” said lead researcher Ruhan Nagra.

Researchers also separated their findings into two zones, a circle including those homes closest to the plant, and an outer ring of households farther away. Those in the zone closest to the plant experienced an even higher rate – 12.4%.

“It supports the local people’s suspicions that this plant was at the root cause of the poisoning of our community,” said Robert Taylor, a local resident who has been organizing to fight emissions levels since 2014. “The closer you are to the plant, the sicker you are.”

Facebook Twitter Pinterest Norco, Louisana. Communities in the area between New Orleans and Baton Rouge are often referred to as Cancer Alley due to a concentration of toxic pollution from petrochemical factories. Photograph: Julie Dermansky/The Guardian

The plant’s operator, a US subsidiary of the Japanese chemical company Denka, as well as the Louisiana Department of Environmental Quality (LDEQ), have consistently argued the community in Reserve are in no immediate danger due to emissions from the Pontchartrain Works emissions.

Denka Performance Elastomers (DPE) spokesman Jim Harris told the Guardian that the company could not comment on the specifics of the report because they were not provided a copy in advance of its publication, but cast doubt on its reliability. “From what we have learned, the study appears to be based on individual interviews rather than scientific analysis of actual cancer incidences,” Harris said.

“Fortunately, there is a neutral state body that does compile and analyze information on cancer incidence, and has for many years – the Louisiana Tumor Registry. The Tumor Registry’s scientific analysis has for years shown that there is no historical or current increase in cancers thought to be associated with chloroprene in the census tracts bordering the facility. In fact, rates near the facility are even significantly lower in some cases.”

The registry, in its most recent report, stated that the term Cancer Alley “has no scientific validity”.

Nagra called their reports “notoriously incomplete”, adding that the registry itself “admits that they don’t collect the type of data needed to determine the existence of associations between industry and cancer”.

A representative from the registry did not immediately respond to a request for comment.

The UNHR study relied instead on responses to a door-to-door health impacts survey of more than 500 households within a 2.5km radius of the plant conducted in March 2018. The analysis compared the real-world survey findings against a computer simulation of a population with the same race, sex and age demographics. “For every resident in our survey sample, we had a corresponding resident – of the same race, sex and age – in our simulated population,” researchers said.

The simulated resident was then assigned as either having been diagnosed with cancer or not, based on data from the National Cancer Institute. Researchers ran the simulation 10,000 times to generate a distribution of possible outcomes for a community with similar demographics.

The methods were developed by epidemiology and statistics experts at Stanford University and, according to Nagra, were done conservatively, largely because they were “aware of the pushback from industry against these types of studies”.

Beyond cancer, the report also offered residents their most conclusive look yet at the prevalence of the other symptoms associated with chloroprene exposure, which include: chest pains, heart palpitations, rapid heartbeat, wheezing, difficulty breathing and rashes on the skin. Since there is no national-level data on how often people experience most of these symptoms, researchers compared the results of residents closest to the plant with those from people who lived farther away. In every single case, there were significantly more symptoms reported in the closer zone.

For residents like Lydia Gerrard, who has long dealt with skin irritation and rashes, the research represents confirmation of what she had long suspected about her decades of exposure to chloroprene while living in Reserve. Gerrard’s husband died from kidney cancer in 2018, and sitting for an interview with the researchers for this study was one of the last things he did before he passed.

“I’m more than sure – that’s where it probably came from,” he told researchers, speaking about the connection between his cancer and the plant, “because that’s one of the cancers that’s been associated with chloroprene.”

Before the full release of the report, Nagra, along with Taylor and Gerrard, traveled to Tokyo, Japan, to present their findings to DPE’s parent company. Nagra said the company responded with “utter defiance” and declined to take a meeting with their envoy.

DPE has made efforts to bring down emissions levels in recent years, having recently hit a targeted 85% reduction, thanks almost entirely to the installation of new emission control technology. The amount of chloroprene in the air still regularly exceeds the 0.2 μg/m3 that the Environmental Protection Agency (EPA) says is acceptable, however.

Nagra sees this report as all the more reason why the company ought to be held rigidly to that standard.

“Eighty-five percent of what it was in 2014 – that’s just not good enough,” Nagra said. “Emissions have got to come down to the EPA guidelines. So this is not a radical position. It’s just it’s self-evident.”

The Guardian, in collaboration with the Poor People’s Campaign, will be hosting a series of events on the Cancer Town series in New Orleans and Reserve on 26 and 27 July.