TALLAHASSEE — After the state scrambled last spring to prevent a potential catastrophe at a former phosphate-plant site, a federal judge will hear arguments Tuesday about whether he should toss out a lawsuit filed by environmental groups alleging “malfeasance” in the handling of hazardous waste.

U.S. District Judge William Jung will hold a hearing in Tampa on motions by the Florida Department of Environmental Protection, Gov. Ron DeSantis and other defendants to dismiss the lawsuit centered on the Piney Point site in Manatee County.

The lawsuit came after about 215 million gallons of wastewater were discharged from the site into Tampa Bay in April because of fears about a potentially catastrophic breach of a reservoir. The lawsuit said the discharges, in part, caused harmful algae blooms and fish kills. Also, nearby residents had to be temporarily evacuated because of fears of a breach.

The Center for Biological Diversity, Tampa Bay Waterkeeper, Suncoast Waterkeeper, Manasota-88 and Our Children’s Earth Foundation allege that the state and other defendants long mishandled the site.

But the Department of Environmental Protection contends that the lawsuit should be dismissed because it is “moot.” The department said a separate case in state court has led to an appointed receiver overseeing efforts to close the site.

But in a Jan. 21 filing, attorneys for the environmental groups said the receiver is engaged in “preparatory work.” Also, they argued that the case involves disputes about broader issues, including what is known as a National Pollution Discharge Elimination System permit for the site.

“There is no plan in place (from the receiver), let alone proposed,” the plaintiffs’ filing said. “Even if the (federal) court were to accept that the receiver will eventually achieve ‘closure,’ that would still leave unaddressed plaintiffs’ claims concerning groundwater contamination and the lack of any NPDES permit. A live controversy exists, and this case is not moot.”

The lawsuit alleges violations of the federal Clean Water Act and a law known as the Resource Conservation and Recovery Act. In the lawsuit, attorneys for the plaintiffs wrote they are seeking to “ensure Piney Point is operated and closed in a manner that complies with the Resource Conservation and Recovery Act and abates the present imminent and substantial endangerment to human health and the environment, including endangered species such as manatees and sea turtles.”

In addition to DeSantis and the Department of Environmental Protection, the other defendants are property owner HRK Holdings LLC and the Manatee County Port Authority — both of which also filed motions to dismiss the case.

Piney Point includes hazardous phosphogypsum stacks, a byproduct of phosphate production, which took place at the site from 1966 to 1999. State and local officials and HRK rushed to shore up the site in April after leaks of wastewater raised concerns about a breach.

Also, state lawmakers earmarked $100 million to help resolve the problems at the site.

“In effect, they (the plaintiffs) argue that every action (or inaction) by an agency employee is automatically imputed, and thereby traceable, to Governor DeSantis,” the document said. “They are wrong. Indeed, they cite zero authority for this sweeping proposition, despite their clear burden to prove standing.”