Toxic ‘wall of water’ threatens city
Locals in Tampa Bay, Florida were sent a text message on Sunday telling them to "Evacuate NOW" as a "catastrophic" 7m wall of toxic water threatened to break through a pond wall.
Officials warned a breach in an old phosphate mine reservoir at Piney Point has the potential to gush out 2.3 billion litres of water within minutes.
The imminent collapse of a storage pod at the reservoir 40 minutes south of Tampa Bay could flood homes and roads with water contaminated with phosphorus and nitrogen.
It would be environmentally disastrous in western Florida's ecologically sensitive Tampa Bay estuary, home to hundreds of species of birds, fish and marine life including manatees and dolphins.
More than 300 homes were immediately evacuated with families placed in hotels, while 345 inmates from Manatee County Jail were moved to an undisclosed location.
On Sunday, Manatee County administrator Scott Hopes said the latest models for the flood showed up to 1.5m of water could cover the jail's lowest storey.
State of emergency declared by Florida Governor
A state of emergency was declared as crews worked to prevent the collapse of the pond and Florida Governor Ron DeSantis flew in to visit the site of the leaking toxic reservoir.
Mr DeSantis tweeted: "Due to a possible breach of mixed saltwater from the south reservoir at the Piney Point facility, I have declared a state of emergency for Manatee County to ensure resources are allocated for necessary response and recovery."
"What we are looking at now is trying to prevent and respond to, if need be, a real catastrophic flood situation," Mr DeSantis said after flying over the old Piney Point mine.
Portions of US Highway 41 that lie near the leaking 31-hectare pond have also been closed off.
The local drinking water supply is said to be unaffected and there is no threat to Lake Manatee, the area's primary water source.
The Florida Department of Environmental Protection says the water in the collapsing pond is primarily saltwater mixed with wastewater and stormwater.
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.
The pond had begun leaking in March after which county officials began discharging water from it.
Pond containment wall could collapse at any moment
Last Friday, a break was detected in a wall of the pond that holds billions of litres of the water contaminated by the old phosphate plant.
Officials tried to plug the hole in the 8m deep pond with rocks and other material, but were unsuccessful.
Then a portion of the pond's containment wall shifted, meaning a collapse could occur at any time.
Workers have been pumping out thousands of litres per minute at the site to bring the volume down in the event the pond bursts.
Meanwhile, Mr Hopes said he planned to double the amount of water being pumped out and hope the risk of collapse could be decreased significantly by Tuesday.
The contaminated water would be transferred to Port Manatee, a nearby large deepwater seaport.
"We're not talking about anything with radiation or high levels of heavy metals," he said.
He added the leak seems to have plateaued and that pumping the entire pond out would take up to 12 days.
Hopes said he could not rule out that a full breach could also destabilise the walls of the other ponds at the Piney Point site.
He said: "The pond is basically saltwater. We saw ducks yesterday, there are snooks swimming in there. It's sustaining wildlife. That's not the case for the other two pools."
Florida Department of Environmental Protection Secretary Noah Valenstein warned another pond has higher levels of metals.
"The radiologicals are still below surface water discharge standards," he said.
"So, again this is not water we want to see leaving the site."
The leaking pond sits in a stack of phosphogypsum, a waste product from manufacturing fertiliser, and contains "small amounts of naturally occurring radium and uranium".
The stacks can also release large concentrations of radon gas.
Environmental groups urged the US federal government to step in.
"We hope the contamination is not as bad as we fear," said Justin Bloom of the group, Suncoast Waterkeeper.
"But (we) are preparing for significant damage to Tampa Bay and the communities that rely on this precious resource."
Originally published as Toxic 'wall of water' threatens US city