Measurements of toxic air pollution in Louisiana’s “Cancer Alley” show pollutant levels far higher than federal estimates, according to recent research led by Johns Hopkins University professor Peter DeCarlo.
Over a month, DeCarlo and his team repeatedly drove a mobile air-monitoring lab from Baton Rouge to New Orleans, through the area scientists call Cancer Alley. The industrial corridor, aptly named for its elevated cancer risks, stretches 85 miles along the Mississippi River, where about 25% of the United States’ petrochemicals are manufactured by over 200 industrial facilities.
The Hopkins team tracked a slew of harmful pollutants — 17 volatile organic compounds, or VOCs, including substances that may cause cancer. The scientists found that one compound, ethylene oxide, made up the bulk of the cancer risk, contributing up to 92.2% of the total cancer risk in some areas.
The United States Environmental Protection Agency’s acceptable risk of developing cancer is 100 people per one million for people living in areas like Cancer Alley. However, in some areas in Cancer Alley, the numbers were as high as 560 people per one million.
Before the Hopkins study, the EPA used AirToxScreen to screen for pollution levels in the area. The new measurements show that, in 14 of 15 areas, cancer risk levels were between 0.9 and 11.6 times higher than those modeled by AirToxScreen.
In much of Cancer Alley, the inaccurate USEPA data were the only quantitative air pollution data available before this research.
DeCarlo said a possible reason for this large discrepancy could be that the values that AirToxScreen uses to model concentration are self-reported by the companies emitting them.
“So a company gets to say, we think we emitted 10 pounds of this over the last year, but nobody’s auditing that, nobody’s checking, right?” DeCarlo said. “That’s the thing that worries me … that a place called Cancer Alley is [being reported] 10 times under what its measured risk is.”
In addition to cancer risk, proximity to urban areas and industrial plants can cause respiratory issues. Mark Mondrinos, assistant professor of biomedical engineering at Tulane University, said higher rates of asthma, chronic obstructive pulmonary disease and emphysema all may result from exposure to air pollutants.
“The airways are getting irritated and inflamed, and that exacerbates the normal [respiratory] processes,” Mondrinos said.
Before this study, there was very little regulatory monitoring data to link the unusually high cancer rates observed among residents to air pollutants. The Hopkins team is using its data as scientific backing to advocate for cleaner air in their parishes.
The Tulane community is situated just adjacent to the southern border of Cancer Alley, but Mondrinos said that living in an urban environment for four or five years probably would not have lasting negative health effects.
Nevertheless, Mondrinos said the elevated risk is something to be vigilant about.
“You definitely need to keep [the cancer risk] in the back of your mind,” Mondrinos said. “That should just be something that you understand as a risk factor.”