What Worsening Floods Mean For Superfund Sites

16:35 minutes

A rope crossing over a dirt road that reads "CAUTION: Radioactive Materials"
The West Lake Landfill has been a Superfund site since 1990. The landfill in north St. Louis holds 300,000 cubic yards of radioactive waste, left over from the nuclear weapons program. Credit: Ashford Kellen for the EPA

Sandwiched between the Missouri River and St. Louis Lambert International Airport lies one of the region’s most toxic waste dumps: a landfill containing thousands of cubic yards of radioactive waste.

A legacy of the nation’s World War II-era atomic weapons program, the radioactive waste at the West Lake Landfill in Bridgeton, Missouri, was deemed such a threat to public health that the federal government stepped in. The dump was added to the Environmental Protection Agency’s (EPA) National Priorities List—also known as the Superfund program—in 1990.

Superfund sites are some of the most polluted areas in the country, containing highly toxic waste such as asbestos, lead, and dioxin. Cleaning them up, which follows a systematic, science-based process as required by law, can take decades.

There are more than 1,300 of these sites across the US, from Florida’s Panhandle to the banks of the Rio Grande in New Mexico. They’re found in nearly every state, often near residential areas. The EPA estimates that 78 million people live within three miles of a Superfund site—nearly 1 in 4 Americans.

But these waste dumps face a growing threat: the worsening effects of climate change. The EPA has determined that more than 300 Superfund sites are at risk of flooding. The actual number of flood-prone sites, however, may be more than twice that amount, according to a 2021 Government Accountability Office report. Floodwaters can move toxic waste into neighboring communities, which threatens drinking water, agriculture, and broader ecosystem health.

As climate change intensifies the frequency and severity of flooding, some Superfund sites are already experiencing the effects. In 2017, at least 13 sites were inundated with floodwaters during Hurricane Harvey, including the San Jacinto Waste Pits near Houston, Texas. At that site, a 16-foot wall of water damaged a concrete cap, exposing toxic waste. Divers from the EPA later found cancer-causing dioxins in the sediment of the San Jacinto River at more than 2,300 times the recommended clean-up level.

American Public Media editor and science journalist Shahla Farzan joins SciFri’s John Dankosky to discuss how flooding threatens these toxic waste dumps—and the challenge of securing them before the worst effects of climate change are felt.

This story was produced by Shahla Farzan. Edited by John Dankosky, with help from Charles Bergquist and Robin Kazmier.

Special thanks to the experts we spoke with: Dr. Rebecca Neumann, Dr. Lara Cushing, and Dr. Konstantinos Andreadis, along with EPA Remedial Project Manager Chris Jump, Missouri State Representative Doug Clemens, and St. Louis activists Dawn Chapman and Karen Nickel.

Further Reading

Segment Guests

Shahla Farzan

Shahla Farzan is a science journalist, PhD ecologist, and editor with American Public Media, where she helps produce science podcasts for kids. She loves showcasing the many weird and wonderful aspects of science—and encouraging young, curious thinkers to question and explore the world around them.

Segment Transcript

MAGGIE KOERTH: This is Science Friday. I’m Maggie Koerth.

JOHN DANKOSKY: And I’m John Dankosky. The first Earth Day in 1970 launched a decade of environmental activism, which pushed US lawmakers to take action. In just the first few years of the 1970s, the Environmental Protection Agency was created and legislation was passed to protect drinking water and save endangered species, among other things. But by the end of that decade, there were still serious environmental problems, including the remnants of decades of chemical pollution.

Our next story focuses on some of the most highly polluted areas of the country, they’re called Superfund sites. And a big chunk of them, more than 300, are found in areas that are in danger of flooding. Shahla Farzan has been reporting on this story for us. She’s a science journalist and editor with American Public Media. Shahla, great to have you back.

SHAHLA FARZAN: Great to be here.

JOHN DANKOSKY: So these Superfund sites are pretty common, right.

SHAHLA FARZAN: Yeah. There’s actually more than 1,300 of these sites across the US. And you can find them in pretty much every state. So there’s a good chance you’ve got one near you. About 78 million people live within three miles of a Superfund site. That’s almost 1 in 4 Americans.

JOHN DANKOSKY: Wow, that’s a big number. So, I mean, what exactly is in these sites.

SHAHLA FARZAN: Lots of different things. So depending on the site, there’s everything from lead and asbestos to radioactive waste. A lot of these chemicals take a really long time to break down and can cause pretty serious health problems like cancer.

JOHN DANKOSKY: Let’s talk about where you live in Missouri, Shahla. A place that has more than 30 of these Superfund sites. And there’s one not too terribly far from where you live in Saint Louis. Could you tell us about this?

SHAHLA FARZAN: Yeah, it’s called the West Lake landfill, and it’s about a mile and a half from the Missouri River. And buried underground, there is about 300,000yd of radioactive waste. It’s hard to know exactly how much is there because radioactive waste just tends to contaminate everything it touches. But it’s enough to fill up more than 18,000 full size dump trucks.

JOHN DANKOSKY: That’s a lot of waste. I mean, how did so much radioactive waste get dumped by a major river anyway? I mean, why do people think that was a good idea.

SHAHLA FARZAN: Yeah, it’s actually left over from the Manhattan Project. So back in the early 40s, right around the time the US entered World War two, a company in Saint Louis started processing uranium ore. And that uranium was used in some of the first atomic weapons tests. And this particular company in Saint Louis made a lot of it, somewhere around 1 ton of uranium oxide every day by 1942.

And in doing so, they also made a lot of waste that they just didn’t know what to do with. So more than 100,000 tons of radioactive waste got dumped across St Louis. Some of it was stored outside in barrels which leaked into a Creek. And a bunch more of that radioactive waste got dumped into a residential landfill.

JOHN DANKOSKY: And that’s the site we’re talking about today, the West Lake landfill. So this radioactive waste is near the Missouri River. Does that area flood?

SHAHLA FARZAN: Yes. So the landfill is behind a levee. But this area definitely can flood and it does. So one of the last times that happened was back in July 2022. We had this series of really intense thunderstorms roll through St. Louis that brought a lot of rain, almost 8 inches in six hours. And by the end, some spots had gotten a foot of rain.

JOHN DANKOSKY: A foot of rain. Wow, so what happened to the Superfund site?

SHAHLA FARZAN: I talked with Don Chapman about that. She’s an activist who lives near the Superfund site and she’s been pushing the government to clean it up for more than a decade. She drove over there in the morning to check on the site, and here’s how she described it.

DON CHAPMAN: Westlake was an island. It was an island. It was flooded on all sides. It had you know, it had built up and come up around the landfill. It never surpassed it and came over the top. But what did happen is the rain fell so fast and so strong that it actually took chunks off the landfill.

JOHN DANKOSKY: Wait, so the rain was washing away chunks of the landfill?

SHAHLA FARZAN: Well, so years before the EPA, who’s the one that’s in charge of the site, had covered the landfill with a special type of fabric and gravel just to try to contain that radioactive waste. But the rain had been so heavy that in some spots it just washed the gravel right into the floodwaters.

JOHN DANKOSKY: So does that mean that there was radioactive contamination washing away, too?

SHAHLA FARZAN: Fortunately, no. I asked Chris Jump about this. She’s the EPA’S remedial project manager for this site. And she said the gravel did wash away in some areas. But when they went back and tested stormwater from about a dozen different spots around the landfill, the EPA didn’t find any radioactive contamination. Here’s Chris.

CHRIS JUMP: We were actually surprised, pleasantly surprised that we had such positive results. I mean, it basically shows that, yeah, there are some steep slopes that have a potential for erosion, but it was controlled to the extent that we didn’t see any migration of the contaminants themselves.

SHAHLA FARZAN: And I should mention that unrelated to this particular flood, the EPA has found that pollution from the landfill is seeping into the groundwater under the site. It’s mostly things like solvents and petroleum products, but small amounts of that radioactive contamination have moved off site.

JOHN DANKOSKY: Let’s get back to Missouri in just a bit. But I want to talk about how this all started in the first place. How exactly do these Superfund sites come to be?

SHAHLA FARZAN: The Superfund program started back in 1980. And what sparked it was this series of high profile environmental disasters in the late 70s. One of them happened in this place called Love Canal in upstate New York. Years earlier, a chemical company had dumped toxic waste into this canal, which eventually started leaching up out of the ground and into yards and basements. And things got really bad, really fast.

Kids were born with serious birth defects like multiple ears and multiple sets of teeth. And eventually the feds actually declared a state of emergency and moved hundreds of families who lived there. And that’s just one example, John, because there was lots of waste being dumped all over the US.

JOHN DANKOSKY: Where exactly was all this chemical waste coming from?

SHAHLA FARZAN: A lot of it was connected to the manufacturing boom that happened after World War II. So people were really eager to spend money on household goods and appliances and cars. So factories started making more stuff and producing more industrial waste. But at the same time, there weren’t that many laws controlling how companies got rid of these chemicals. So they just kind of dumped them wherever they wanted, which usually was Rivers and streams and landfills.

And this was happening everywhere, but manufacturing hubs like Saint Louis really got the brunt of this pollution. I talked with Missouri State representative Doug Clemens about this. He grew up in St Louis, right next to a Creek contaminated with toxic waste.

DOUG CLEMENS: I’m from Northwest county, Saint Louis. We were post-world war two, the industrial base for Missouri. You know, we had Ford, we had a refrigeration company. We had a paint company. We had all of these areas which have left behind contaminants. It was very convenient for factories to just leave things behind or put them out the back door, which have soaked into the soil.

JOHN DANKOSKY: But like we said, by the late 1970s, it sounds like, I don’t know, this was starting to change.

SHAHLA FARZAN: Yeah, that’s right. I mean, more people were getting worried about this, and that put pressure on US lawmakers. So by 1979, lawmakers were holding hearings on toxic waste. And by the following year, they’d passed legislation on it, which created the Superfund program. And that program is managed by the EPA. And the goal is basically to force polluters to clean up these sites.

JOHN DANKOSKY: OK, so let’s fast forward to the present. We know that climate change is making flooding more intense and more frequent, and we know that hundreds of these Superfund sites are in areas that can flood. How about the chemicals that are actually being moved around by this flood water?

SHAHLA FARZAN: Yeah, it’s a good question. So there’s three main ways that these chemicals can move around in the flood waters. So you can have water flowing over contaminated dirt and moving that dirt around. You can have chemicals that are already in water like maybe a contaminated pond, and then the flood mixes with that polluted water. Or you can have chemical reactions happening where the water actually reacts with the pollutants in the sediment, and then those chemicals are released up into the water.

JOHN DANKOSKY: But then where do they end up? I mean, are they going to storm soars into rivers?

SHAHLA FARZAN: Well, it’s going to depend on a lot of different factors, honestly, like what kinds of chemicals are there. Is the land pretty flat or hilly? Even how fast the floodwater is moving.

JOHN DANKOSKY: And could they seep into the ground and contaminate drinking water, too.

SHAHLA FARZAN: Yeah, that can happen because groundwater and surface water are a connected resource. So if a flood, let’s say, sweeps through a Superfund site, some of that contaminated water can flow back into the river and then some could seep underground into groundwater.

JOHN DANKOSKY: Well, that sounds concerning.

SHAHLA FARZAN: Yeah, it does. But there’s an important caveat here that I think we should mention, and I heard it from Becca Newman. She’s an associate professor at the University of Washington, and she studies how contaminants move around in the environment. And she said it’s not just whether a specific chemical is there or not because every chemical is going to be a little bit different in terms of how it moves in the environment, how it affects human health. Here’s what she said.

BECCA NEWMAN: So what matters is its concentration and the nature of the chemical. So there are some chemicals that we can say are contaminating the landscape, but are having minimal impact on human health or minimal impact on ecosystem health. And then we can have other chemicals that, you know, extremely trace levels that are almost non-detectable that could actually be quite harmful. So it’s not just its presence that matters, it’s like these other pieces.

SHAHLA FARZAN: And John, that’s what makes this issue so hard to study. There are just so many different types of toxic chemicals out there. And we’re just starting to understand a lot of them, in terms of their health impacts, even sometimes their basic chemistry. So one scientist might spend their entire career just trying to understand one chemical when there are thousands of others out there in the environment.

JOHN DANKOSKY: And it seems like that could make things pretty complicated. I mean, especially if we’re talking about sites with decades of pollution, we don’t know everything that’s in there. Now, you talked about the human health impacts, who exactly is most at risk here?

SHAHLA FARZAN: It varies from site to site, but you usually find Superfund sites in communities that are low income and whose residents are mostly people of color. Part of this has to do with racial discrimination and all the different ways it’s affected housing practices and limited where people of color live.

JOHN DANKOSKY: Yeah, and I imagine that these communities are already pretty vulnerable.

SHAHLA FARZAN: Yeah, that’s the thing. I mean, they’re already less equipped to handle environmental disasters like, let’s say, a big flood that washes pollution from a Superfund site. I talked with Lara Cushing about that. She’s an assistant professor of Environmental Health Sciences at UCLA. Here’s what she said.

LARA CUSHING: You know, during flood events, low income households have fewer resources to prepare and weather these events. So low income households and families of color are also less likely to have adequate insurance, more likely to rent their home as opposed to owning it, and as a result, not benefit as much from federal assistance after natural disasters. And they’re more likely to be displaced after major flood events.

SHAHLA FARZAN: Again, 78 million people live near a Superfund site. But this is something that affects everybody, whether you have one of these sites in your city or not, because we’re talking about water, right. Like river systems in the US are totally interconnected. They cross state lines, they filter into aquifers and into groundwater. There’s something that our ecosystems obviously depend on, not to mention our agriculture.

JOHN DANKOSKY: It raises the question about what to do with all this information, Sheila. I mean, we’re talking about things getting worse in the future. Maybe we can talk about how well this program is working now.

SHAHLA FARZAN: If we just look at the raw numbers, the EPA’S cleaned up more than 450 Superfund sites since the program first started. But there’s still more than 1,000 left on that list and more being added constantly. One of the main criticisms of this program is that it’s slow, like it can take years or sometimes even decades for a site to get cleaned up. And sometimes that has to do with funding and bureaucracy. But a big part of this is that the EPA follows a pretty rigorous, science based process for each site. And sometimes science just moves much slower than what we’d want it to.

JOHN DANKOSKY: So what about more flooding that might come with climate change. Is that something that the EPA’S planning for?

SHAHLA FARZAN: Yes, so the EPA has been aware of this issue for years. Back in 2012, they evaluated how vulnerable each Superfund site was to climate change effects, so not just flooding, but also things like wildfires. And they’ve been training their project managers on how to incorporate climate change risk into the cleanup plans for each Superfund site. But a lot of this climate change planning is Supersite specific. So what you do to secure one site in California might be really different from what you do for another site in Missouri.

JOHN DANKOSKY: So, yeah, let’s go back to St Louis and that Superfund site near the Missouri River that we talked about earlier, the West Lake landfill. Is the EPA taking climate and flooding into account there?

SHAHLA FARZAN: So they do have a plan to clean up the radioactive waste at the landfill. And as part of that planning, they’re using climate modeling to predict what things might be like at the site in the future. And the model suggests the site’s going to get an additional inch of rainfall every month by 2050. And it’s also going to have more violent rainstorms.

JOHN DANKOSKY: Sure I mean, we’re talking about radioactive contamination, though, right. I mean, that’s something that sticks around for a long time.

SHAHLA FARZAN: Yeah, absolutely. Plus, there’s still going to be some radioactive waste left behind at this site even after cleanup is finished. And you’re right, that waste takes a really, really long time to break down, in some cases, thousands of years. And no one knows what the future is going to look like at this site 500 or 1,000 years from now.

JOHN DANKOSKY: How do you even plan for something that far in the future.

SHAHLA FARZAN: Yeah, I asked Chris Jump about that. Remember, she’s the EPA’S remedial project manager for the landfill. And she said that when it comes to climate change specifically, it’s a lot easier to plan for the worst case scenario now and include that in the cleanup design, then try to go back and fix things later.

CHRIS JUMP: Because we’re doing the design right now, now is the perfect time to design those preventions into the plan. It just makes sense to do it to try and plan for worst case scenario while we’re constructing it so we don’t have to go back when we have some kind of a failure.

SHAHLA FARZAN: And Chris acknowledged that the community is impatient and they want this process to move faster. And I think that’s the tension in a lot of communities, not just Saint Louis. You have toxic waste that needs to be removed. A climate crisis that’s threatening a lot of these sites and a sometimes slow moving cleanup process. And so I think the question that we’re left with is, can we clean up or at least secure these waste dumps before the worst effects of climate change are felt?

JOHN DANKOSKY: That was science journalist and editor Shahla Farzan. Thanks so much for sharing this reporting with us, Shahla.

SHAHLA FARZAN: Thanks so much for having me.

JOHN DANKOSKY: If you’d like to learn more about Superfund sites around the US that might be at risk during floods, you can go to sciencefriday.com/Superfund. Thanks also to Saint Louis Public Radio for their help with that story.

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Meet the Producers and Host

About Shahla Farzan

Shahla Farzan is a science journalist, PhD ecologist, and editor with American Public Media, where she helps produce science podcasts for kids. She loves showcasing the many weird and wonderful aspects of science—and encouraging young, curious thinkers to question and explore the world around them.

About John Dankosky

John Dankosky works with the radio team to create our weekly show, and is helping to build our State of Science Reporting Network. He’s also been a long-time guest host on Science Friday. He and his wife have three cats, thousands of bees, and a yoga studio in the sleepy Northwest hills of Connecticut. 

About Charles Bergquist

As Science Friday’s director and senior producer, Charles Bergquist channels the chaos of a live production studio into something sounding like a radio program. Favorite topics include planetary sciences, chemistry, materials, and shiny things with blinking lights.

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