DeSantis on Saturday declared a state of emergency in Manatee, Hillsborough, and Pinellas counties against the possibility as state and local officials oversaw evacuations.
The Florida governor said the state has been pumping approximately 33 million gallons per day into Tampa Bay since Thursday to decrease stress on the leaking containment walls to avoid a breach and flood.
"What we are looking at now is trying to prevent, and respond to if need be, a real catastrophic flood situation", DeSantis told a press conference after viewing the site by helicopter Sunday.
Manatee County Public Safety Department said that 316 households are within the full evacuation area.
A portion of the reservoir's retaining wall shifted laterally, which means total structural collapse is possible, Manatee County public safety officials said.
A significant leak at a large pond of wastewater threatened to flood roads and burst a system that stores polluted waters.
It has elevated levels of phosphorous and nitrogen and is acidic, but is not radioactive, reports said, despite it containing small amounts of naturally occurring radium and uranium.
"We are talking about the potential of about 600 million gallons (2.3 billion liters) within a matter of seconds and minutes leaving that retention pool and going around the surrounding area", Hopes said.
Officials saw recently, an increase of water that leaks out but Hopes said it appears to have plateaued.
Florida Governor Ron De Santis warns of flood threat Credit Chris O'Meara AP
Jeff Barath, manager for HRK Holdings at Piney Point, held back tears while briefing Manatee County commissioners on the incident Thursday, the Tampa Bay Times reported.
But "we are not out of the critical area yet", he warned.
The Florida DEP Secretary Noah Valenstein said another pond has higher levels of metals.
Hopes explained he could not rule out that an entire breach could disrupt the walls of other ponds located at the Piney Point site.
"The radiologicals are still below surface water discharge standards", he said.
The concerns for the quality of the water being discharged are now "less than the risk of everyone's health and safety" due to the potential for flooding, DeSantis said Sunday.
The U.S. Environmental Protection Agency has a coordinator on the scene to work with emergency management and provide support as necessary, said EPA spokeswoman Brandi Jenkins.
Environmental groups have urged the federal government to step in to halt sending more wastewater to the existing "gypsum stacks" and halting the generation of more phosphogypsum which is left behind when phosphate rock gets mined to generate fertilizer. "We can take care of nutrients in the environment".
Calls to the owner of the site, HRK Holdings, for comments went unanswered Saturday and Sunday.
The ponds are said to have been sitting in stacks of phosphogypsum, a solid radioactive byproduct from manufacturing fertilizer, as explained in Daily Kos.