PALMETTO, Fla. — The Piney Point phosphate plant opened near the shores of Tampa Bay in 1966 and only a year later was caught dumping pollution that tainted some of the bay's most popular fishing grounds.

The facility has been plagued ever since by repeated violations and problems. The most recent came over the weekend, when local officials evacuated more than 300 homes and blocked a major highway because of fears that a reservoir holding millions of gallons of industrial wastewater could fail. Such a breach, officials warned, would send a 20-foot wall of water slamming into the community near where the reservoir was leaking.

Over the years, state and local governments have been reluctant to take the steps that would resolve the trouble with Piney Point. But this latest near-calamity may finally push them to act. Even as they continue pumping wastewater from the reservoir to relieve the pressure on its weakened walls, officials are reviving a controversial cleanup proposal and suggesting an of-the-moment way to pay for it.

The plan: to treat the plant’s polluted water and inject it 3,500 feet below ground and into a salty part of the Floridan Aquifer. The $200 million to do this would come from President Biden’s covid-recovery package.

Critics say that local leaders’ solution, which was first considered in 2013 and then rejected, might make things far worse. If tried here, they worry, it might also be attempted elsewhere in Central Florida at the two dozen similar facilities where radioactive-phosphate processing waste is stored in mountainous stacks topped with vast ponds of acidic liquid.

Local farmers are particularly concerned about the impact that deep-well injection would have on the aquifer. Yet some are so weary of the repeated crises at Piney Point that they’re ready to give the plan a try.

“It’s not something we’re happy about, because our irrigation wells are in close proximity to Piney Point,” said Alan Jones, who grows potatoes. “But considering the latest brush with catastrophe, maybe this is the best-case scenario so we can put this thing to rest for all time.”

In Washington, the wastewater leak has prompted calls for Biden to include more money in his infrastructure plan for repairing aging dams and reservoirs. His proposal sets aside $50 billion to improve infrastructure resilience, only a portion of which would go to dam safety.

The Piney Point plant, originally built by Borden Chemical, once turned mined phosphate rock into fertilizer to be shipped around the nation. It sits just south of the Sunshine Skyway Bridge, an area that’s a mix of small farms, industrial sites and mobile home parks flying both Canadian and American flags, and across U.S. Route 41 from Port Manatee. The current owner, HRK Holdings, which has been in and out of bankruptcy, has used the site recently to dispose of material dredged from ship berths.

The highway was reopened Tuesday and the evacuation order lifted. Late in the afternoon, the Manatee County Commission voted unanimously to pursue the deep-injection plan.

“This allows us to dictate the quality of the water before it goes into the wells,” Chairwoman Vanessa Baugh announced at a news conference.

Florida Environmental Protection Secretary Noah Valenstein signaled the state’s agreement, saying that interim measures would be implemented as construction of the injection wells is planned. The permitting process could take two years or longer, he noted.

The plant has passed through a number of owners ill-equipped to deal with its waste. As early as 1970, local newspapers reported massive toxic algae blooms in nearby Bishop Harbor — a state aquatic preserve — caused by pollution from the plant flowing into a creek that runs to the bay.

“Fish Paradise Polluted Anew,” a Tampa Tribune headline declared.

Scientists fear a similar result from this latest round of dumping, because the wastewater being sent into Tampa Bay contains high levels of phosphorus and nitrogen, elements of nutrient pollution.

Local communities have spent billions of dollars since 1991 to clean up the nutrients contaminating the bay — at 400 square miles, the state’s largest estuary — and to encourage the regrowth of sea grass. Much of the bay is now as clean as it was in the 1950s, but this concentrated slug of Piney Point pollution is likely to rewrite the story.

“It’s frustrating, for sure,” said Ed Sherwood, executive director of the Tampa Bay Estuary Program. “This is going to turn back the clock.”

The millions of gallons of pollution are expected to fuel another large algae bloom, which can devastate sea grass and suck the oxygen out of the water, killing thousands of fish. That’s what happened in 2003 and 2011, two years when Piney Point was in crisis mode.

The seeds for the current crisis were sown in the 1990s, when, according to an investigation by the St. Petersburg Times, state environmental officials repeatedly bent the rules to allow the phosphate plant to continue operating despite clear signs of financial instability. As long as the plant was running, its wastewater could be recycled for use, limiting the possibility of an overflow.

But in 2001, then-owner Mulberry Corp. declared bankruptcy, shut off the pumps and walked away. The U.S. Environmental Protection Agency stepped in briefly before passing the problem off to the Florida Department of Environmental Protection.

Desperate to get rid of the pollution without further damage to the bay, the state agency obtained special EPA permission to load millions of gallons of the toxic liquid aboard a barge and take it out into the Gulf of Mexico for disposal.

HRK bought the plant in 2006, and company executives and Manatee County commissioners decided in 2013 to pursue state permits to inject Piney Point’s remaining wastewater into deep wells.

“There was significant opposition from the local community,” said Glenn Compton of the local environmental group ManaSota-88, which also opposes allowing any other phosphate facilities to dispose of their waste in the same way.

The farmers’ opposition was particularly loud that year, given fears that the waste would migrate into the part of the aquifer used for irrigating crops as well as supplying private wells used for drinking water.

In 2016, as they were on the verge of winning permit approval, Manatee County officials reconsidered and withdrew their application.

Former commissioner Joe McClash, who is now chairman of the Suncoast Waterkeeper environmental group, is no more convinced today.

“The problem with these deep wells is you just don’t know where things will pop up in a generation or so,” he said Tuesday. “It’s just like the thinking that got us into this situation to begin with. If people knew then what we know now, they would never have built that plant where they did.”

Dino Grandoni in Washington contributed to this report.