‍BALTIMORE (March 27, 2025) — A new peer-reviewed study published in Environmental Health Perspectives establishes a first-of-its-kind index to measure the combined impacts of multiple toxic air pollutants on human health. Developed by researchers at Johns Hopkins University, this new method found elevated risks of diseases that would have been entirely overlooked under traditional risk assessment used by regulatory agencies. The new approach more accurately characterizes the cumulative burden of breathing many different air pollutants that fenceline communities are exposed to daily and has uncovered broader risks, including to the lungs, brain, kidneys, and endocrine system. 

“Communities living on the fenceline of heavy industry are much more exposed to toxic air pollution, and our findings show that the combination of the chemicals they breathe puts them at risk of an array of different, life-threatening health harms other than cancer,” said Keeve Nachman, Professor of Environmental Health and Engineering at Johns Hopkins University. “Our new approach to understand the burden of these combined exposures is a significant step toward truly characterizing the real dangers these communities face.”

The findings demonstrate that the traditional approach used by the Environmental Protection Agency (EPA) and other regulators significantly underestimates non-cancer health risks faced by people living near industrial polluters like petrochemical plants. These standard approaches to risk assessment typically tackle each pollutant on a one-by-one basis, underestimating that toxic chemicals can target multiple organ systems in the body and that groups of chemicals may act together to cause a greater variety of diseases. The new approach considers the full scope of health risks from simultaneous exposure to dozens of toxic chemicals to provide a more holistic estimation of the effect of the chemical mixture on communities.

The Hopkins team used the approach to document the risks faced by Southeastern Pennsylvania communities living in the shadow of petrochemical processing facilities, but the methodology can be replicated in any other community contending with exposure to air pollution.

"A single toxic chemical can devastate the health and safety of a community—and communities overrun with petrochemical facilities are exposed to dozens," said Heather McTeer Toney, executive director of Beyond Petrochemicals. “We can’t manage what we don’t measure. For too long, our systems of accountability have relied on industry estimates and outdated risk assessments while communities have paid the price. Thanks to the researchers at Johns Hopkins, we now have a clear, replicable method to measure the cumulative risk from petrochemicals in our air."

Johns Hopkins researchers, in collaboration with Aerodyne Research, used a mobile laboratory with state-of-the-art technology to measure 32 different hazardous air pollutants in communities on the fenceline of industrial facilities. These compounds include formaldehyde, benzene, toluene, ethylbenzene, and xylenes, all of which are air pollutants known to be dangerous to breathe.

“The ability to accurately measure these hazardous chemicals in the air in real-time gives us a better understanding of the pollution the community is living with on a daily basis,” said Peter DeCarlo, Associate Professor of Environmental Health and Engineering at Johns Hopkins University. 

This new approach to characterize cumulative risk shows neurological, renal, respiratory, endocrine, and systemic risks in their study area. Traditional monitoring previously found no risks. These risks only increase for vulnerable populations—like seniors, children, pregnant women, and immunocompromised people—and for those facing other life burdens, like poor nutrition, limited access to healthcare, life stress, and other health conditions.

“Our findings in Pennsylvania are likely similar to the risks faced by many communities living near large industrial operations like petrochemical facilities,” said Nachman. “We plan to apply this new approach in a variety of fenceline communities in the near future, but it is already clear that the current approach to risk assessment is not measuring up.”  

These results prompt the need for stricter air pollution standards, improved monitoring of pollutants, and risk management approaches that fully account for cumulative risk to inform policy decisions and protect the health of overburdened communities. After deep staff cuts and rollbacks in bedrock protections, the future of public health protections from hazardous air pollution looks increasingly uncertain and bleak. For decades, the EPA’s funding has struggled to keep up with the real demands of keeping Americans safe and healthy, especially in communities adjacent to high concentrations of industrial facilities. Nearly 40 percent of Americans live within three miles of a hazardous facility.

“While new science is showing the health effects of petrochemical pollution are worse than we thought, the EPA is getting weaker, and the industry is gearing up for a massive expansion,” added McTeer Toney. “We are proud to invest in this groundbreaking science to fill the gap and stand beside communities fighting for their lives.”

The team of researchers who have worked on this new index submitted a comment last month on a proposed Biden-era rule for cumulative impact monitoring. The EPA recently announced it intends to reconsider the rule. You can read the researchers’ comments here.

Read the full paper here.

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MEDIA CONTACT: Matt Smelser, [email protected]

About Beyond Petrochemicals:

Launched by Bloomberg Philanthropies in September 2022, Beyond Petrochemicals: People Over Pollution aims to halt the rapid expansion of petrochemical and plastic pollution in the United States.The campaign draws on the success of the Beyond Coal campaign, supported by Bloomberg Philanthropies, and Bloomberg’s Beyond Carbon campaign, to turbocharge existing efforts led by frontline communities to block the rapid expansion of 120+ petrochemical projects concentrated in three target geographies – Louisiana, Texas, and the Ohio River Valley. The campaign also works to establish stricter rules for existing petrochemical plants to safeguard the health of American communities. To date, Beyond Petrochemicals has helped raise awareness and lead timely collaboration efforts using its four pillars of grassroots and litigation, data and research, policy and advocacy, and narrative shift to accelerate its goals. For more information, please visit us at beyondpetrochemicals.org and follow us on Instagram, LinkedIn, Facebook, and X.