'Imminent' reservoir wall collapse threatens to pollute Tampa Bay

Manatee County's acting administrator Scott Hopes said inmates and staff at the local jail had been moved to the second floor of the two-story building as a precaution.

Toxic ponds (above) at the old Piney Point phosphate mine where environmentalists have urged the United States government to intervene.

Problems at the Piney Point reservoir stretch back decades.

"We're hoping that we can just continue to get water out in an efficient way to prevent a catastrophic event", the governor said.

Ron DeSantis said Sunday that crews are working to prevent the collapse of a large wastewater pond in the Tampa Bay area while evacuating the area to avoid a "catastrophic flood".

The Florida Department of Environmental Protection says the water "meets water quality standards for marine waters with the exception of pH, total phosphorus, total nitrogen and total ammonia nitrogen".

Amid the heightened threat, Manatee County Public Safety Department expanded an evacuation order to hundreds of homes in the surrounding area. Now about 22,000 gallons of water are being discharged per minute, and Hopes said he expects the risk of collapse to decrease by Tuesday. Pumping the entire pond would take 10 to 12 days.

Florida Commissioner of Agriculture Nikki Fried, noted that the leak is not the first at the property, in a letter to DeSantis on Saturday calling on him to convene an emergency session of the Florida Cabinet.

Crews have been discharging water since the pond began leaking in March. The agency did not immediately respond to a request for comment.

Billions of litres of contaminated water threaten to flow from the breached pond at the old mine.

After a large sinkhole opened up in a phosphogypsum stack pond in 2016, more than 200 million gallons of polluted wastewater from another fertilizer plant in central Florida leaked into one of the state's largest aquifers.

Hopes said he could not rule out that a full breach could destabilize the walls of the other ponds at the Piney Point site. The pond at the reservoir contains small amounts of naturally occurring radium and uranium, and the stacks can also release large concentrations of radon gas. We saw ducks yesterday, there are snooks swimming in there.

"The breach release is traveling in the direction that we anticipated and planned for so we believe that probably by Tuesday we're going to be in a much better position and the risk level will have decreased significantly with the governor's assets", said Hope.

Florida's agriculture commissioner, Nicole Fried, wrote to DeSantis saying the current emergency was only the latest in a hard history at the facility.

Phosphogypsum is a byproduct of fertilizer from phosphate rock, and is considered to be weakly radioactive.

There are at least 70 gypsum stacks in the United States and about 27 in Florida, mostly in the region of west-central Florida. Since the piles covering the structure can exceed 500 feet in height, the gypsum stacks' pollutants cannot be seen from the ground.