Homes were evacuated and a highway was closed off near the large reservoir as hundreds of million of gallons of acidic, radioactive water might be leaked into the surrounding neighborhoods.
"Evacuate area NOW. Collapse of Piney Point Stack Imminent!" read an alert from county officials about 11 am Saturday.
The 79-acre reservoir holds nearly 400 million gallons of water containing phosphorus and nitrogen from the old phosphate plant.
The spillage is an “imminent hazard” which poses “an immediate and substantial danger to human health, safety, welfare and the environment,” said Gov. Ron DeSantis, who issued an executive order declaring a state of emergency.
An initial leak in the reservoir was reported on March 26 but the situation has gotten worse in recent days. On Friday, a break was detected in one of the walls of the pond that has a depth of 25 feet (8 meters).
Rocks and materials were brought in to plug the hole in the pond late Friday into Saturday, but the attempt was not successful.
Around 10:00 on Saturday morning, the on-site engineers “deemed the situation to be escalating,” said Manatee County Public Safety Director Jacob Saur.
One containment wall shifted to the side, he said, signaling a structural collapse could happen at any time.
“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,” Manatee County Administrator Scott Hopes said at a press conference Saturday.
If the side wall breaches, it would "create a substantial opening," resulting in hundreds of millions of gallons escaping, according to Hopes.
"We've been trying to contain this water unsuccessfully for 20 something years," Hopes said.
Agriculture Commissioner Nikki Fried called on Florida Gov. Ron DeSantis to hold an emergency session of the state cabinet to discuss a plan.
“The immediate evacuation of residents, disruption of families during Easter weekend, and potential environmental catastrophe requires the attention and action of Florida’s statewide elected leadership,” Fried said in a letter.