Manatee County Administrator Scott Hopes said at a press conference on Saturday that the most pressing concern is that the water could flood the area, which he said was agricultural and low in population density. Authorities closed off portions of the U.S. Highway 41 and ordered evacuations of 316 homes.
Officials said the 77-acre (31-hectare) reservoir holds millions of gallons of water containing phosphorus and nitrogen from an old phosphate plant. "I have also deployed the National Guard and they are in the process of dropping off additional pumps via aircraft on top of the berms, to help decrease the water levels in the Piney Point reservoir at an even faster pace".
Hopes said he could not rule out that a full breach could destabilize the walls of the other ponds at the Piney Point site.
"Water quality issues that are flowing from this, for us, is less than the risk of everyone's health and safety, particularly folks who may live in the area", DeSantis noted.
Aerial images aired on local television showed water pouring from leaks in the walls of the retention pond.
Hopes said he hoped the emergency would inspire a permanent fix for phosphate stacks following decades of neglect.
"The radiologicals are still below surface water discharge standards. So, again this is not water we want to see leaving the site", he said.
In 2016, more than 200 million gallons of contaminated waste water from another fertiliser plant in central Florida leaked into one of the state's main aquifers after a massive sinkhole opened up in a pond of a phosphogypsum stack.
Officials are rolling out a response plan that includes controlled discharges of mixed seawater into Port Manatee to relieve pressure and maintain the integrity of the stack system, according to the Florida Department of Environmental Protection.
"We are closely monitoring the ongoing situation and are in close communication with Governor DeSantis' office, as well as the Florida Department of Environmental Protection", she said in an email.
DeSantis vowed to hold HRK Holdings, the owners of the property, accountable for the failure.
Fried details in her letter how previously-known poor maintenance by current and former phosphate mine owners have created a unsafe situation for local residents, communities and even state-managed lands and waters.
Hopes said the plan is not to fix the damaged reservoir liner.