Duke Energy alerted Florida’s environmental regulators Aug. 20 about a chemical spill at its power plant on the mouth of the Anclote River in Pasco County, according to a state pollution report.
A plant technician early Thursday morning found an estimated 3,200 gallons of sodium bisulfite had spilled outside the plant in Holiday and onto the surrounding soil and asphalt, the company said in an incident report. Another 500 gallons were contained to the building.
In a statement to the Tampa Bay Times on Aug. 24, a Duke Energy spokesperson said none of the chemical made it into the river and that cleanup on-site was nearly complete.
“There were no impacts beyond the plant site, and no actions or precautions are necessary by neighboring properties,” wrote company spokesperson Ana Gibbs.
State regulators confirmed there were no impacts to nearby waters, a Florida Department of Environmental Protection spokesperson said. The spill occurred when a ladder fell overnight and broke a valve, the agency said.
The chemical, often a white, crystal-like powder, has a sulfur odor and can irritate human skin, according to the National Institutes of Health. Industries often use the compound to remove chlorine while treating wastewater.
The plant technician found a line that feeds the chemical had breached. Duke Energy’s lead environmental consultant, Robert Stafford, reported the spill to state regulators. The company sent two contractors, Arcadis and Republic Services, to clean up the chemical, according to the pollution report.
There are two main ways sodium bisulfite could be harmful, and it would depend on whether it washed into the water or stayed on land.
If it had entered nearby waterways, the chemical could have removed oxygen from the marine ecosystem, potentially harming slow-moving wildlife that can’t escape the chemical. If it stayed in piles on land, people near it could have breathed in unhealthy gases that irritate the lungs, according to John Osegovic, a professor who teaches chemistry at the University of South Florida in St. Petersburg.
The risk level depends on how much of the chemical was spilled, where it went and how concentrated it was, Osegovic said.
“It’s not something you can just leave around; it needs to be collected and contained,” he said.
The power plant pumps freshwater from the Anclote River to cool its steam generators before discharging that water into the Gulf of Mexico, a plant manager told Spectrum Bay News 9 in 2024.
The plant celebrated 50 years of operation that year. The Anclote station, which sits 20 feet above sea level, stayed open through back-to-back hurricanes Helene and Milton in 2024.
The plant discharges salty water as part of its regular operation, permit records show.
Boilers and a reverse-osmosis treatment system at the 480-acre site create industrial wastewater that is stored in ponds at its west end, according to a 2021 state environmental agency report.
The wastewater percolates in the ponds before it is discharged to groundwater, the report states.
Since 2005, the state has given the plant a “groundwater quality” exemption. The exemption allows the plant’s groundwater discharges to exceed the drinking water quality requirements for sodium of 160 milligrams for every 1 liter of water. Duke’s discharges can reach up to 4,000 milligrams under the exemption.
The plant’s monitoring wells have shown there’s been “no sodium increases to groundwater due to the plant’s activities,” the company wrote in its latest exemption application.
The power plant is mostly surrounded by brackish water, with the Anclote River to the south and a canal to the east that separates the facility from the mainland. The Holiday area had heavy rainfall around the time of the spill: about 1.4 inches, most of which fell in the morning, according to the National Weather Service.
Doris Carroll, vice president of the Democratic Environmental Caucus of Pasco, warned that the chemical depletes oxygen in water and can kill fish.
“Pasco DECF is calling on Duke Energy and FDEP to release all soil and surface-water sampling, to confirm whether the spill was released before, during, or after rainfall ... and confirm the spill has not reached local drainage or the river or the Gulf,” she wrote in a statement.
Tampa Bay Waterkeeper, an environmental nonprofit that regularly tests water quality around the region’s watershed, said it was aware of the spill.
“The spill has been reported to appropriate state authorities and we will continue to monitor the cleanup and the measures implemented to prevent future spills from occurring,” executive director Justin Tramble said in a statement.
“This is important given how close the facility is to the Anclote River,” Tramble said.
Times staff writers Emily L. Mahoney and Michaela Mulligan contributed to this report.
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