Sixty percent of the nation's heavily polluted Superfund sites—nearly 950 of them—are at risk from the impacts of climate change, including hurricane storm surges and flooding that could spread their toxic legacies into waterways, communities and farmland, a new federal report warns.

The U.S. Government Accountability Office report, released Monday, describes the increased risk of toxic substances being washed out by flooding at sites across the country, as well as wildfire risks that could send health-harming pollutants airborne.

It recommends that the Environmental Protection Agency, which oversees the federal Superfund program, start providing clear, agency-wide instructions on how its officials should incorporate climate change into Superfund site risk assessments and response decisions.

That would be a change for the current administration. Currently, the EPA does not include climate change in its agency-wide goals and objectives, preventing the agency from addressing the added risks at contaminated sites across the country as the planet warms, the report concluded.

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"The Superfund program is not providing necessary resources and direction to regional officials that would help them assess and respond to site-specific risks due to climate change," a dozen members of Congress, led by Sen. Tom Carper, the top Democrat on the Senate Environment and Public Works Committee, wrote in a letter to EPA Administrator Andrew Wheeler in response to the report.

"The lack of resources for regional offices is a direct result of EPA headquarters' failure to embrace addressing climate change as a strategic objective," the letter stated.

Of the nearly 1,600 "national priority list" Superfund sites not on federal land that were examined in the report, more than half are at increased risk from flooding or storm surge.

One example is a site in Bridgewater, New Jersey, with contaminated soil and groundwater from 27 unlined chemical waste lagoons stemming from more than 90 years of chemical and pharmaceutical manufacturing. The site is in a 100-year flood zone and could be reached by the storm surge from powerful hurricanes. Heavy rains from Hurricane Irene flooded the site in 2011, though subsequent testing by EPA concluded no significant release of contaminants occurred.

Another example is the San Jacinto River waste pits near Houston. Dioxins, chemicals that can cause cancer and liver and nerve damage, were dumped in and near the San Jacinto River from paper mills in the 1960s. In 2010, the EPA required the paper mills responsible for the cleanup to install a temporary cap over the waste. Since installation, however, the EPA has observed repeated damage to the cap, including during Hurricane Harvey in 2017, damage that led to high levels of dioxins detected in the area.

More than 200 sites are at increased risk from wildfires, the GAO found. One example highlighted in the report is the Iron Mountain Mine site near Redding, California. Acidic runoff from the mine includes copper, cadmium and zinc that are toxic to fish and other aquatic life. In 2018, the Carr Fire nearly destroyed the site's water treatment system, and fire was subsequently discovered inside a pipe leading into the mine that could have led to an explosion had it reached the mine.

The GAO also found that nearly 100 Superfund sites would be inundated if sea level rose by 1 foot.

Globally, sea level has risen 7 to 8 inches since 1900, and it is expected to rise another half foot to 1.2 feet compared to 2000 levels by 2050, according to the National Climate Assessment. In its report, the GAO also cites the National Climate Assessment's warnings about how rising global temperatures exacerbate hurricanes, storm surges, wildfires and flooding.

An interactive graphic from the GAO shows the climate-related risks facing each Superfund site.

EPA Regions' Responses

Investigators with the GAO, Congress's watchdog, reviewed documents from federal agencies and interviewed EPA officials about the how climate risks were being assessed at Superfund sites at the request of members of Congress.

EPA officials in six of the agency's 10 regions said they have not used climate change projections for flooding or rainfall in Superfund site assessments, according to the report.

Officials in Region 6, an area that includes Texas and several other surrounding states, told GAO investigators that they do not incorporate any potential impacts of climate change into their assessments.

Peter Wright, an assistant administrator for the agency, wrote in response to the GAO report: "The EPA strongly believes the Superfund program's existing processes and resources adequately ensure that risks and any effects of severe weather events, that may increase in intensity, duration, or frequency, are woven into risk response assessments."

'Just the Beginning'

What we have seen so far is "certainly just the beginning," said Michael Gerrard, director of the Sabin Center for Climate Change Law at Columbia University.

"All the projections are that coastal storms and inland precipitation have nowhere to go but up, and that is going to steadily increase the number of Superfund sites that are vulnerable," he said.

Other contaminated sites that are not considered in the current report will also be increasingly susceptible to the impacts of climate change, Gerrard said. "There is a much larger universe of contaminated sites that could also be vulnerable."