Milton likely to hit Florida's phosphate mining hub, worrying environmentalists

Environmental groups are worried about possible pollution impacts as Hurricane Milton is likely to pass directly over Bone Valley, Florida, the heart of the state's phosphate mining and production.

According to a Tampa Bay Times analysis, 22 of Florida’s 25 phosphate waste piles are located in Hurricane Milton’s projected path over Manatee, Hillsborough and Polk counties. That’s according to the latest National Hurricane Center forecast and state environmental regulatory data as of Wednesday morning.

Mosaic, a Fortune 500 phosphate mining company headquartered in Tampa, said that it is “preparing locally for the storm both professionally and personally” at the several plants it operates in the region.

The company oversees a plant on the northeastern shores of Tampa Bay, in Riverview, and another further inland in Mulberry, among others. Their mounds of regulated phosphate waste are hundreds of feet tall and contain phosphogypsum, a mildly radioactive byproduct of the phosphate manufacturing process. These stacks also contain ponds of polluted wastewater used to create fertilizer.

As of Wednesday morning, Tampa Bay was forecast to see up to 12 feet of storm surge and damaging winds from what could be a Category 4 storm at landfall.

“We are worried that a direct hit from a storm as powerful as Milton could be catastrophic,” said Ragan Whitlock, an attorney for the Center for Biological Diversity, a nonprofit that has sued to increase phosphogypsum regulations.

A spokesperson for Mosaic, Ashleigh Gallant, said if there are impacts to these phosphoygypsum stacks, or “gypstacks,” that the company would “release those publicly after the storm.”

Mosaic prepares for hurricanes by conducting drills, inspecting its plants and making sure its test pumps, generators and other equipment is onsite and working, according to a website outlining its operations. After the storm, Mosaic staff assess damage and offer support to employees who have been personally affected by severe weather. A spokesperson for the Florida Department of Environmental Protection did not immediately respond to a request for comment.

Still, environmental watchdogs remain concerned.

“There are several phosphogypsum stacks situated precariously close to Tampa Bay’s waters,” Whitlock said. “We hope these facilities emerge from the sustained 100+ mph winds expected for the area unscathed, but open-air ponds of hazardous waste with historic structural integrity problems create a well-founded concern.”

Earlier this year, Mosaic confirmed to state environmental regulators that there was a tear in the protective liner beneath its gypstack in Mulberry. In 2016, a sinkhole stretching 152 feet opened beneath the gypstack and resulted in 215 million gallons of contaminated water draining into the aquifer below.

Many living in the Tampa Bay area also remember 2021, when millions of gallons of tainted water were sent from the Piney Point phosphate plant in Manatee County into the bay as a precaution due to fears that a leak in a reservoir could trigger a massive flood, endangering nearby homes and businesses. Last month, a judge ruled against the plant’s former owner, HRK Holdings, and ordered the company to pay more than $800,000.

Now, as the state has ordered the plant’s permanent closure, crews were on site earlier this week making sure it was prepped ahead of Milton.

“We spent a good amount of time earlier this week getting ready,” said Herb Donica, a lawyer and the court-appointed overseer of the plant. Donica has required every contractor on the site to have a written hurricane plan, and the site closed ahead of Milton at noon Tuesday.

Donica’s main concern is for his team’s mobile office. While it’s battened down, any sustained damage to the office would be “an interruption that we don’t want to have.”

It’s not safe for anyone to be on site during the storm, Donica said, and Piney Point’s managers have evacuated ahead of the anticipated hurricane-force winds from Milton.

“We are the most prepared that we can be,” Donica said.

(Tampa Bay Times staff writer Shreya Vuttarulu contributed to this report.)