Hurricane Florence's toxic soup

With flood waters still rising in parts of the Carolinas, concerns over what is in the water are growing.

With total rainfall of up to 36 inches (91 centimeters), Florence has killed at least 40 people, and cleanup efforts are estimated to cost at least $17 billion (€14.5 billion). But more than just homes and seaside tourist sites have been damaged by the storm.

Environmental hazards loom from overflowing industrial waste sites. It harkens back to the secondary mess left by Hurricane Harvey in Texas last year.

Hog waste and coal ash

According to North Carolina environmental regulators, several hog farms' open-air manure pits have failed due to flooding.

North Carolina is the second-largest hog farming state in the US. At the time of reporting, the state's Department of Environmental Quality says 31 swine lagoons (hog waste holding areas) have overflowed, six have incurred structural damage, and a further 99 are at risk of overflowing.

An estimated 5,500 hogs and 3.4 million chickens and turkeys have been killed by the storm.

State officials also reported a breached coal-ash landfill on September 15 near Wilmington, North Carolina. Coal ash is a byproduct of burned coal, and contains toxic lead, arsenic, mercury and other heavy metals.

According to the company Duke Energy, coal ash leaked into local waterways including Sutton Lake from its LV Sutton Power Station, though Duke reports that it has since stemmed the leak.

Storms of Florence's size, like last year's Hurricane Harvey, pose a threat to public health and ecosystems when infectious bacteria and toxic chemicals leak into flood waters.

"The general public should be aware of that elevated threat and take precautions," Will Hendrick, a staff attorney at the Waterkeeper Alliance in North Carolina, told DW. "Our primary concern right now is public health."

Toxic soup

Sewage may be the kind of contamination that first comes to mind after intense flooding — but industrial waste poses a major threat.

Large-scale farms store hog manure, which holds dangerous bacteria like salmonella, in open lagoons. Such lagoons are designed to handle 19 inches of rainwater — but they're no match for a mega-storm like Florence.

Farms spread waste from lagoons on fields as fertilizer. But with little time for the soil to absorb the manure before storms hit, the waste mixes into floodwaters.

North Carolina regulators are still unable to access the worst-hit farming areas to assess bacteria levels in waterways.

State inspectors have been able to visit the breached coal-ash landfill at Duke's Sutton power station and are awaiting test results to determine whether Duke Energy violated clean water rules.

Duke Energy said in a statement that "initial test results announced Wednesday demonstrate that lake water quality is good." State regulators and environmental groups have yet to verify these findings.

Flooding has also inundated three other Duke Energy sites, releasing coal ash and other potentially toxic coal burning byproducts.

Harvey's lasting mess

Toxic waste leaks are a looming threat after hurricanes — especially as climate change makes hurricanes more severe.

During Hurricane Harvey last year, the most notable incident occurred at a flooded chemical plant in Texas that released organic peroxides. These chemicals — used to make paint, plastic and medicine — then exploded.

At another chemical plant in Texas, half a billion gallons (1.89 billion liters) of industrial wastewater mixed with storm surge water, allowing toxic substances like vinyl chloride, butadiene, benzene, and other human carcinogens to enter neighboring areas.

Earlier this year, the Associated Press and the Houston Chronicle compiled government records revealing more than 100 instances of toxic discharges from chemical plants, refineries, and oil, gas and chemical pipelines due to Hurricane Harvey.

Only last month did environmental authorities begin enforcing action against some of the companies responsible for these plants.

Preparing for future storms

Speaking about hurricanes Harvey and Florence, Tom Knutson, a NOAA climate scientist specializing in hurricanes, told DW: "These storms traveled rather slowly over certain regions, so they were able to dump a lot of accumulated rain."

With a warming climate, hurricane rainfall is projected to increase by about 15 percent over the next century. Rising sea levels will also enhance storm surge.

Identifying vulnerabilities and establishing stronger regulations prior to major storms is one way hurricane-prone areas can prepare against future flooding.

"Duke Energy should never have dumped its coal ash into unlined pits, sitting in groundwater next to rivers throughout the state," Frank Holleman, a senior attorney at the Southern Environmental Law Center, told DW.

Holleman's colleague at the Southern Environmental Law Center, Geoff Gisler, suggests buyouts for the most vulnerable hog waste sites, as well as a move away from open lagoons.