Let’s say you live next to a highway, and you also get your drinking water from a municipal source that’s contaminated by “forever” chemicals. Your body wouldn’t process the polluted air independently of the polluted water you’re drinking; these pollutants would act together. Or let’s say you’re exposed to a hazardous chemical in your workplace: the effects of that exposure don’t clock out when your shift is done and you go home. Sources of environmental pollution are not evenly spaced, they don’t operate in isolation, and regular people are not exposed to just one pollutant at a time. Unfortunately, our environmental regulatory system doesn’t consider the effects of multiple pollutants, or risks from different sources, on our health.
The study of these interactions, and how they can accumulate, is known as cumulative impacts analysis. And the US government only recently began working to update its guidance about exposure to pollution based on cumulative impacts.
In late 2024, the U.S. Environmental Protection Agency (EPA) released a document designed to help EPA incorporate a cumulative impacts approach into its science and policymaking. To give the public appropriate and meaningful input, EPA solicited public comments on this framework, getting opinions from experts and advocates on using cumulative impacts analysis to improve public health and the environment. Unfortunately, when President Trump appointed Lee Zeldin as the new administrator of EPA, this process came to a halt. EPA has not responded to any of the public comments nor made any moves to implement or even finalize this framework.
Since then, the Union of Concerned Scientists has worked with government, environmental justice, and public health experts to review and analyze public comments and get a better understanding of how cumulative impacts analysis can be put to work to improve people’s lives. Those findings were released in a new report, Unfinished Business.
Dr. Kristie Ellickson of the Center for Science and Democracy at UCS was the lead author on this new report. A longtime cumulative impacts researcher, she says that in the absence of federal action, states, community advocates, and scientists alike have an opportunity to put the lessons of cumulative impacts to work to improve people’s lives.
AAS: First things first: what is cumulative impacts analysis?
Kristie Ellickson: “Cumulative impacts” is both a concept and a tool—fundamentally, it means matching environmental protections with the way people actually experience pollution. Too often, the rules for different pollutants—or for different kinds of exposures, like in the workplace and the home—don’t “talk to” each other. You can’t look at a single pollutant in a vacuum. You need to bring in other factors, to look at people’s living conditions and what kinds of other pollution they’re exposed to. You need to understand things like access to health care, access to food, the effects of racial discrimination. To do that, you need to connect different kinds of information and the work of different agencies, so you can make more holistic decisions.
This could look like an environmental agency using data from a health agency to find out about hospitalization rates in a community. It could look like a permitting agency consulting a map to see what other facilities or pollution sources are located close to the facility applying for a permit. The overarching concept is that you need to look at multiple kinds of information to make good decisions.
AAS: What’s your background with this topic? How have you used cumulative impacts analysis in your work?
KE: I worked for 14 years as a staff scientist for the state of Minnesota. In 2008, Minnesota passed a law requiring a cumulative impacts approach for an environmental justice area in Minneapolis. For decisions about air permits, the state needed to examine not just the proposed facility’s pollution, but also existing pollution, health data like emergency room visits due to asthma attacks, as well as social conditions like poverty rates and historical racial discrimination. As a staff scientist, I was tasked with getting input from the affected communities and incorporating it into our analysis. And as a result of that new requirement, I saw real reductions in the amount of pollution that was allowed in these permits.
There’s a lot of really interesting science here. I love to work with maps and data sets, and I have seen the value of cumulative impacts analysis in action. This isn’t just research for research’s sake—these assessments should be connected to decisions, and the information used to make sure those decisions get us to a real-world outcome. The science is there to support this approach if decisionmakers choose or are required to use it.
For the last four years, I’ve worked at UCS, starting as a fellow with a two-year project to create a Community Guide to Cumulative Impacts. We’ve worked collaboratively with community partners and a range of experts to help people understand what cumulative impacts analysis is and how to use it. It’s so crucial that we match environmental protection efforts with how people actually experience pollution, and that those communities are a central part of the process of designing these assessments and making policies. The words and wisdom of people who live and breathe environmental justice issues were incorporated into the guide.
I also co-chaired a working group of the EPA’s National Environmental Justice Advisory Council (NEJAC) to write up cumulative impact guidance for the federal government. A goal of the NEJAC was to bring a variety of perspectives to the table, including regionally. The United States is big and geographically diverse, with a wide range of ecosystems and climates, and you can’t design good policies based on a single set of assumptions. We also looked closely at racial disparities—the goal is to reduce pollution overall, but also to reduce how disproportionate pollution exposures are in our country.
One important part of this is pairing different kinds of expertise. There’s quantitative work—measuring the lead levels in soil, counting children with high lead levels in their blood—but you have to consider people’s lived experience as well. You can’t understand, or solve, environmental issues without that context, combining the stories and expertise from people who live in affected communities with more traditional quantitative data. As a UCS fellow, I co-authored a peer-reviewed study on these “mixed method” approaches for the journal Environmental Justice in 2024.
AAS: How did the EPA get involved with cumulative impacts analysis?
KE: Community groups have been advocating for a cumulative impacts approach for decades—and this call has also been put forth by major advisory groups, including NEJAC in 2003 and 2004, the National Research Council in 2009, and the National Academies of Science, Engineering and Medicine last year. At the end of the Biden administration, EPA published this document, the Interim Framework, to lay out how the agency could understand cumulative impacts and put these tools to work, as a response to this long-running effort. Then, they opened a 90-day period for public comment. That period straddled two administrations, and when President Trump was inaugurated, the federal government took a hard turn away from this approach. The Trump administration (and the new EPA administrator Lee Zeldin) eliminated the two offices in EPA that did the most to produce the framework: the Office of Research and Development and the Office of Environmental Justice and Civil Rights. They also eliminated the NEJAC and other advisory boards. And they simply did not respond to any of the comments or even acknowledge them. So the framework and all the comments on it were sitting in the public register. That’s incredibly valuable data, and that motivated us to look at and preserve these comments, which the Trump administration was largely ignoring.
AAS: How did you approach the framework and the comments?
KE: UCS partnered with some independent researchers, including people who formerly worked for or advised the EPA. We did a rigorous analysis of these comments to find the common themes and input on how to make cumulative impact assessment effective. This, too, was a mixed-methods process, in which we looked at the comments themselves but also spoke with people who wrote comments, people who served on those disbanded advisory committees, and people who have been doing education and organizing around cumulative impacts. We held four different convenings to talk about the framework and the comments.
One thing that really came through was the importance of accountability. You can’t set up effective policies without measures for enforcement. The law tells you what you should do, the rules tell you how you do it, but you also need integrated accountability and enforcement so those rules actually work in practice to benefit people.
Another aspect is the value of a public health perspective that incorporates the experience of health practitioners, and a labor perspective that accounts for people’s experience in the workplace.
One thing that was very helpful to understand was: people are surprised that cumulative impact analysis isn’t already the default approach. It’s common sense to people, and they’re surprised to learn that policies and permitting decisions don’t take existing pollution and stressors into account.
Another striking thing is how the people we invited to these convenings really showed up engaged and ready to work hard to keep making progress. While we do a lot of work at UCS on existing harms and impacts and the attacks on science that are happening right now, cumulative impacts is a way of looking forward to the future, to make environmental protections that are really protective in the long term.
AAS: What are the next steps for this work? What do you hope happens with this report and the conversations you’ve had around it?
KE: As a courtesy, we sent the report to everyone who included their contact information in their comment. We’ve also sent our report to the EPA, so that it’s on the record, and they know we’re watching. But the White House and their EPA appointees are so explicitly hostile to science, to environmental justice considerations, to environmental protection in general that we know there won’t be much progress on this at the federal level under this administration. But that doesn’t mean the effort is over.
At least seven states have cumulative impacts laws or regulations, and there are a number of city and local ordinances as well, mostly aimed at air pollution permitting. We can expand these policies, and more states and communities can adopt them, and we hope this report offers useful information about what people with both academic and lived expertise want to see. We could see cumulative impacts used as a lens for county-level zoning and planning processes, for example. This is a resource that people all around the country can use to find ways to implement a cumulative impacts approach. For UCS, the next step is to broaden our conversations to bring in different kinds of expertise and experience, and to convene people to create policy roadmaps that state or local governments can adopt going forward.