EPA proposes a new cleanup plan for a portion of the Mississippi Phosphate Superfund Site
A public meeting and official comment period will be held for the new plan
PASCAGOULA, Miss. (March 17, 2025) – The U.S. Environmental Protection Agency (EPA) invites the public to comment on a Proposed Plan to remediate Operable Unit 3 (OU3) of the Mississippi Phosphates Corporation (MPC) Superfund site in Pascagoula, Mississippi. The EPA will present its plan to construct a new on-site wastewater treatment plant (WWTP) at a public meeting on Monday, April 7, 2025, from 6 – 8 p.m. at the Pascagoula Senior Center, located at 1912 Live Oak Avenue in Pascagoula. A 30-day public comment period runs from March 24, 2025, through April 23, 2025.
“I am proud to announce that we are proposing a plan to construct a new wastewater treatment plant to prevent toxic wastewater from impacting Bayou Casotte,” said EPA Region 4 Administrator Kevin McOmber. “EPA has worked with MDEQ and the local government to develop a comprehensive solution that will improve site operations and ensure effective management of discharges that will improve water quality over time.”
The EPA is working to prevent toxic wastewater from impacting Bayou Casotte, where it has proven harmful to fish and other wildlife. With support from the Mississippi Department of Environmental Quality, the EPA is proposing a plan to construct a new wastewater treatment plant (WWTP) adjacent to the East Gypsum Stack to treat wastewater long-term. This follows the 2023 purchase of the former MPC manufacturing plant area by Seven Seas Terminals, LLC for use as a dry bulk storage and tank terminal operation and would allow the new owner to redevelop the land where the existing WWTP sits.
The WWTP would use the same methods that have been in use since 2018 to successfully treat the leachate/contact water and wastewater. The water treatment methods reduce fluoride, phosphorous and nitrogen compounds as well as residual acidity, in leachate so that it can be safely discharged into Bayou Casotte. This leachate will continue to be generated by the stacks – even once they are both closed and capped – for years to come.
The preferred cleanup plan for OU3 complements the ongoing cleanup action at OU2, which encompasses the East and West Gypsum stacks. Before the EPA’s cleanup work began, one inch of rainfall on the East Gypsum Stack produced about nine million gallons of wastewater that threatened Bayou Casotte and needed to be treated before being discharged. Work to close and cap the East Gypsum Stack began in 2018 and has already significantly reduced the amount of leachate that requires treatment. By comparison, the West Gypsum Stack that was closed by MPC in the mid-2000s still generates an estimated 20,000 gallons of wastewater per day that must be treated.
The EPA evaluated two other methods of treating the wastewater as well as taking no action. The preferred alternative builds on methods that have already been successful and is cost-effective.
A copy of the proposed plan and instructions for submitting comments may be found online at: epa.gov/superfund/ms-phosphates-corp.
Background
MPC manufactured DAP fertilizers at its facility, located at 601 Industrial Road in Pascagoula, from the late 1950s until it filed for bankruptcy in October 2014. As a result of former phosphate ore processing operations, including phosphoric and sulfuric acid plants, the soil at the Site is contaminated, primarily by heavy metals, radium-226 and low pH. Groundwater beneath the former plant contains elevated metals concentrations and low pH, generally located in the central portion of the property. The EPA placed the Site on the Superfund National Priorities List in January 2018 and is overseeing the ongoing cleanup of the Site.
More information about the MPC Superfund Site: epa.gov/superfund/ms-phosphates-corp
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