This story was originally published at Science Friday — a weekly program exploring the world of science, technology, and other cool stuff.
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 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 U.S., 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.
The Superfund program first began in 1980, after a series of high-profile environmental disasters pushed the issue of toxic contamination into the spotlight and pressured U.S. lawmakers to take action. The law that created the program, known as the Comprehensive Environmental Response, Compensation and Liability Act, is a cornerstone of U.S. environmental policy – and forces polluters to clean up contaminated areas.
But these waste dumps face a growing threat: the worsening effects of climate change. The EPA has determined that more than 300 Superfund sites nationwide 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.
In Missouri, 24 of the 33 Superfund sites are in areas that can flood, based on data from the EPA. These areas include regulated floodways and 100-year floodplains. An additional six sites in Missouri are in regions with reduced flood risk, such as those protected by levees, while the remaining lie within areas of undetermined flood hazard.
Floodwaters can move toxic waste into neighboring communities, threatening drinking water, agriculture, and broader ecosystem health. Superfund sites are often located near low-income neighborhoods where the majority of residents are Black and Latino – communities that are already burdened by other forms of pollution, such as poor air quality.
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 and edited by John Dankosky, with help from Charles Bergquist and Robin Kazmier. Music and sound design by D. Peterschmidt.
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.
