When a mile-wide tornado roared through Joplin, Mo., it killed 158 people and injured thousands. And it also kicked up toxic remnants from the city’s industrial past that are still haunting its residents on the third anniversary of the disaster.

“Trees were uprooted, houses were leveled, everything underground was now on the surface,” said Leslie Heitkamp, Joplin’s lead inspector and remediation coordinator.

Before the tornado, the southern part of this city of 50,000 had almost no lead contamination but afterward, about 40 percent of yards were contaminated. “We’re still cleaning up yards every day,” she said.

Starting in the early 1800s, people flocked to Joplin to mine lead. Despite a Superfund cleanup in the 1990s, the tornado had no trouble stirring up some of the 9 million tons of toxic wastes left behind from hundreds of mines and 17 smelters.

As tornado season ramps up, and some natural disasters become more common across the United States, experts warn that storms and floods can bring smelters’ ugly past back to the surface.

A nationwide study of 229 shuttered smelters found almost 30 percent are located in areas prone to floods, earthquakes, tornadoes and hurricanes.

“The potential for natural disasters stirring up forgotten toxics is huge,” said Dr. Robert K. Kanter, a professor of pediatric critical care medicine at SUNY Upstate Medical University who led the research.

California had 15 former smelter sites at risk from natural disasters, with Pennsylvania close behind with 14. New York and Missouri had the next two highest totals with seven and six, respectively, and Illinois had five.

Lead smelters, which mostly closed down in the United States by the 1980s, processed ore in a blast furnace to extract the metal. Lead particles, along with arsenic and other toxic substances, were emitted from the plants.

Low levels of lead reduce children’s IQs and are linked to attention and behavioral disorders, according to the Centers for Disease Control and Prevention.

“The ideal solution would be to completely clean up former lead sites,” Kanter said. “But if that’s not possible, the solution is not to ignore and deny the possibility that a disaster will reveal it at the worst possible time.”

Since the 1970s U.S. hurricanes have been more intense and frequent, with 13 of the last 17 years having “above normal” tropical storms and hurricanes, according to a 2012 State of the Climate report. 

In addition, because of global climate change, the areas of the United States at risk of floods may rise up to 45 percent by 2100 due to rising seas and more severe weather, according to the Federal Emergency Management Agency.

Different disasters can have different effects on legacy contaminants, said Jean Brender, a professor of epidemiology and biostatistics at Texas A&M University who was not affiliated with this study. Tornadoes and hurricanes would be more likely to cause airborne lead, depositing the toxics on soil. Children who play in the dirt are at risk, she said.

In addition, flooding could transport lead to surface water. Municipal water providers test for lead but private wells would still be at risk, Brender said.

It’s impossible to know what natural disasters will do to buried contaminants, Kanter said. After hurricanes Rita and Katrina, soil lead levels declined in 63 percent of census tracts in New Orleans. Apparently, floods carried away the contaminants. 

But we can’t count on natural disasters always carrying toxics away, Kanter said.

“The point is if a local community knows about a former industrial site, and knows there are deposits there, that should be a focus for some planning, rather than wait for people and children to be exposed,” he said.

More than 600 lead smelters, from small shops to large factories, operated in the United States between the 1930s and 1960s.  Cleanup nationally has lagged behind because the Environmental Protection Agency had been unaware of many old smelting sites. A recent USA Today investigation found that federal and state officials in most cases failed to check on or clean up the sites. 

Former smelter sites that are designated as federal Superfund sites and are undergoing cleanup still carry danger, said Jim Gawel, as associate professor of chemical and environmental engineering at the University of Washington, Tacoma.

“They essentially draw an artificial boundary around a site,” Gawel said. “But it’s not like the contaminants will magically stay within those boundaries.”

EPA spokesperson George Hull said the agency doesn’t have plans or research specific to the dangers of lead smelters and natural disasters.

The states deemed most at risk in the new report also have no emergency plans for smelters.

In California, the state Environmental Protection Agency has not done any preplanning for former lead smelters in areas prone to natural disasters, said spokesperson Amy Norris. Handling of hazardous materials post-disaster would take into account how the land was previously used, she said.

Pennsylvania also does not have any emergency planning specific to lead smelters during natural disasters, said Cory Angell, a press secretary with the state’s Emergency Management Agency. “We have an all-hazards approach to disaster planning, which would include any potential for lead contamination,” Angell said.

Most former lead smelters in Pennsylvania in Kanter’s study are “cleaned up or in the process of being cleaned up,” said Kerry Leib, director of the Emergency Response Program for the Pennsylvania Department of Environmental Protection.

Every county in Illinois has a local emergency planning coordinator who knows where former lead smelters are, said Kim Biggs, a spokesperson for the Illinois Environmental Protection Agency, in an emailed response. “Illinois EPA will consult with the coordinators in the event of a natural disaster or other emergency,” she said.

Brender thinks the states’ lack of emergency planning for smelters is a mistake. “With all of these former smelters, this study should be an impetus for us to be proactive,” she said. “Before these disasters happen, agencies should look into where the contamination is.”

In Joplin, the EPA estimates that decades of lead processing created about 150 million tons of toxic wastes, with about 9 million tons still remaining after a federal Superfund cleanup. Before the cleanup began in the mid-1990s, about 2,600 homes near former smelters and mining waste sites had elevated lead in their soil. About 14 percent of Joplin children had blood lead levels above the federal health guideline at the time; after the cleanup, it declined to 2 percent.

Since the tornado, the rate of children with elevated lead levels has remained unchanged, Heitkamp said, probably because the ravaged area is mostly uninhabited.

Joplin has spent about $3.5 million so far to clean up lead where the tornado tore through, Heitkamp said. The city now requires that builders in the tornado zone test for lead and, if needed, clean it up, before construction.

The people of Joplin are well aware of their industrial history and tornado risk, Heitkamp said. But that doesn’t mean the city can protect everyone from lead the next time one roars through.

“Unless we tested every individual property, to about five feet below ground, I really don’t think there’s any way to prevent this from happening on some level again,” Heitkamp said.

This article originally ran at Environmental Health News, a news source published by Environmental Health Sciences, a nonprofit media company.