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Phosphate processing plants in the greater Tampa Bay region have caused some of Florida's worst environmental disasters. Accidents like the spill at the former Piney Point plant fill the history books in Florida.

Timeline: Key developments at the Piney Point phosphate plant

Water at Piney Point
Daylina Miller
WUSF Public Media

Here are the key developments at the troubled Piney Point phosphate plant, including a spill that prompted officials to pump more than 200 million gallons of the reservoir’s polluted water into Tampa Bay.

The Piney Point phosphate plant in Manatee County has had several spills, with the latest coming in 2021, when 215 million gallons were released into Tampa Bay to relieve pressure from a leak.

Now, the digging of a deep well at the plant has been completed, and workers will inject millions of gallons of polluted water deep underground.

Here is a timeline of events, from the time the phosphate plant was first built, and the spill that dumped millions of gallons of contaminated water into Tampa Bay.

ALSO READ: A deep well injection could herald the end of spills from the Piney Point phosphate plant


  • Piney Point is first built by the Borden Chemical Company. The facility processes phosphate rock into fertilizer.


  • The company dumps polluted wastewater from the facility into nearby Bishop Harbor, resulting in fish kills.


  • Piney Point changes hands among multiple owners.
  • Toxic gas from Piney Point operations is released into the air.
  • A sulfuric acid leak at the facility spurs an evacuation.


  • The Mulberry Corporation buys Piney Point, but the facility faces financial troubles.
  •  A dam breach and heavy rains cause high water at the site and the eventual dumping of wastewater into the Alafia River, resulting in a fish kill.
  • Water from the phosphogypsum stacks leak underground. FDEP fines Piney Point for these leaking ponds.


  • Piney Point owners face more financial struggles.
  • Mulberry Corporation’s permit renewal for Piney Point is denied by the state.


  • Piney Point’s owners, Mulberry Corporation, file for bankruptcy and abandon Piney Point. It no longer functions as a phosphate processing plant.
  • The U.S. Environmental Protection Agency, then FDEP, take over the site.
  • Hurricane Gabrielle causes Piney Point’s ponds to overflow, and more wastewater is pumped in Bishop Harbor.


  • The state works to close Piney Point permanently and treat its wastewater, but heavy rains complicate the process.
  • The Cargill company takes over and will be responsible for the site’s cleanup.


  • The state continues dumping wastewater from Piney Point into Bishop Harbor, leading to algal blooms and fish kills.
  • Hurricane Francis causes a hole in one of the facility’s dikes, resulting in a wastewater leak.


  • HRK Holdings buys the property and plans to use it as a site to store dredge material, or sediment that is removed from the bottom of bodies of water to reshape land and water features and develop navigation tools, like boating channels. The company is tasked with maintaining the phosphogypsum stacks and the wastewater ponds.


  • The U.S. Army Corps releases a 72-page study warning against storing the dredge material, which it says might be catastrophic and cause a breach in Piney Point’s liner.


  • A wastewater leak caused by the dredging project results in an emergency discharge of millions of gallons of wastewater into Tampa Bay.


  • State officials first consider a plan to inject Piney Point wastewater deep underground.



  • Officials warn that there are leaks in Piney Point’s reservoir liner above the water level and that there may be more failures below the surface. HRK, the owners, also identify flaws in the liner.

March 2021:

  • A leak in the containment wall liner is discovered.
  • To reduce pressure on the leak, officials begin pumping more than 200 million gallons of the reservoir’s polluted water into Tampa Bay.

April 2021:

  • Responding to the risk of catastrophic flooding should the leak become a full-fledged breach in the liner, around 300 homes, as well as businesses and the nearby Manatee County Jail are evacuated.
  • Gov. Ron DeSantis declares a state of emergency in the surrounding counties.
  • The pumping is halted to allow officials to use technology to treat the remaining water before releasing more. 
  • Florida State Sen. Jim Boyd introduces an amendment to the state budget that would allocate $3 million to the cleanup effort, but officials note that total remediation could cost up to $200 million. DeSantis says that he will also redirect $15.4 million from the Florida Department of Environmental Protection’s existing budget toward the cleanup. 

May 2021:

  • Environmental groups publish a notice of intent to sue over the Piney Point crisis.

June 2021:

  • In late June, the five environmental groups officially file a lawsuit in federal court against the governor, state and operators of Piney Point. It asks a federal judge to oversee the clean-up, closure and investigation of the old plant site and to ensure the waste is properly disposed of.
  • FDEP again seeks toissue a permit to allow for pumping the contaminated wastewater deep underground, but faces objections from environmental organizations who say the pumping could contaminate the aquifer and Florida’s groundwater.

August 2021:

December 2021:

  • The state seeks to dismiss the environmentalists’ lawsuit, stating they are already doing enough to fix the problem.
  • The permit for the injection well is finally approved an issued.

January 2022

  • Piney Point still holds 397 million gallons of wastewater. Officials worry about how rainfall will affect water levels at the site.

February 2022

March 2022:

  • The state approves a plan to close Piney Point. Officials predict the plan may be completed by December 2024.
  • The state has now spent $85 million on cleanup since the March 2021 leak.

March 2023:

  • The digging of a deep well at the troubled Piney Point phosphate plant in Manatee County has been completed. Now, workers will soon inject millions of gallons of polluted water deep underground.