The Portsmouth Naval Shipyard in 2019. Shawn Patrick Ouellette/Staff Photographer

The U.S. Environmental Protection Agency has removed the Portsmouth Naval Shipyard in Kittery from its National Priorities List of contaminated Superfund sites after 30 years of extensive remediation.

Removal of contaminated soil, sediment and other hazardous materials at the 278-acre shipyard is complete, and no future remediation is required, the agency announced Friday. However, ongoing operation, maintenance, land use controls and monitoring activities will continue at the site as needed.

The Navy also will continue to conduct comprehensive follow-up reviews every five years and submit them to the EPA to ensure the Superfund remedies continue to protect human health and the environment, the agency said in a statement. Deletion from the list does not prevent future actions under the Superfund law.

The shipyard was established as a government facility in 1800 on Seavey Island in Portsmouth Harbor, at the mouth of the Piscataqua River, where shipbuilding dates back to 1690, the agency said. The first government-built submarine was designed and constructed at the shipyard during World War I, and a large number of submarines have been designed, constructed and repaired at the facility since then.

Contamination at the shipyard resulted from shipbuilding and submarine repair work, waste landfill operations, spills and leaks from industrial operations and piping, storage of batteries and other materials, filling of land and outfalls to the river, according to the EPA.

The shipyard was added to the Superfund list in 1994, after an investigation of several areas in and around the facility found groundwater, soil and sediment contamination, including polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbon (PAHs), metals and benzene, the EPA said.


The EPA deletes sites or portions of sites from the Superfund list when no further construction is required to protect human health or the environment, said David Cash, the agency’s New England regional administrator.

“We’ve achieved a major milestone to get this site where it is today and remove it from the National Priorities List,” Cash said.

Maine’s congressional delegation also praised the accomplishment, with Rep. Chellie Pingree, D-1st District, saying the cleanup “marks the start of a new chapter for Portsmouth Harbor, where shipbuilding has thrived for hundreds of years.”

The EPA formally proposed deleting the shipyard from the Superfund list last August and provided a 30-day public review and comment opportunity. No comments were received.

Today, the restricted-access military facility employs about 5,000 civilians and 200 active military personnel whose primary mission is to convert, overhaul and repair submarines for the U.S. military.

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