NOAA via Getty Images

The EPA is now monitoring 40 toxic sites in Hurricane Florence’s path.

On Wednesday, the Environmental Protection Agency told CNN it was monitoring nine of the nation’s most polluted sites—known as Superfunds—ahead of the sure-to-be historic storm. But on Thursday afternoon, as Florence’s storm surge began to deluge North Carolina’s outer banks, the agency updated that number to 40.

In an emailed press release, the EPA said it had identified 29 highly polluted sites within the potential impact zone of Southeast Virginia, which include Superfunds, large oil facilities, and other facilities that handle “extremely hazardous substances.” The agency also said it identified 11 Superfund sites in the coastal areas of North and South Carolina that could be affected by the storm. The EPA said it was in the midst of compiling a list of Superfund sites in Georgia that could e see impacts from the hurricane as well.

When Superfund sites or other contaminated areas are hit hard by flooding and heavy rainfall, they risk poisoning surrounding floodwater, soil, and people—mostly low-income, minority people, as those populations are more likely to live near toxic sites. This happens all the time, as I reported last year:

After Hurricane Sandy devastated New York and New Jersey in 2012, officials had to monitor 247 Superfund sites—one of which, the Gowanus Canal, overflowed into people’s homes. Nine Superfund sites were in the path of Hurricane Katrina, and several flooded. Thomas Burke, an associate dean at the Johns Hopkins School of Public Health who conducted an assessment of chemical exposures after Katrina, said these inundations very likely contributed to the mass of various chemicals found in soil and groundwater after the storm. “It’s hard to say for sure because there was not specific site evaluation data included in our assessment,” he said. “But absolutely, Superfund sites were a major potential source of soil and groundwater contamination. They always are after major hurricanes.”

Unfortunately, Superfund sites aren’t the only major potential source of soil and groundwater contamination from Hurricane Florence. The storm’s likely path also runs through dozens of unlined lagoons of animal feces and coal waste, which threaten to overflow into adjacent drinking water sources.