EPA finalizes cleanup plan for the Lower Passaic River

The U.S. Environmental Protection Agency has announced finalization of an interim plan to clean up contaminated sediment in the upper nine miles of the Lower Passaic River Study Area of the Diamond Alkali Superfund site in New Jersey.


The lower 17 miles of the Passaic River is a study area of the Diamond Alkali Superfund site. While the greatest volume of contaminated sediment lies in the lower 8.3 miles of this 17-mile stretch, contamination in the upper nine miles acts as a continuing source of contamination in the river, affecting fish, wildlife and communities along the riverbanks.

EPA’s plan calls for the removal or isolation under a cap of the contamination sources, with the goal that the work is done at the same time as work already planned for the lower 8.3 miles of the river.

The action is interim, meaning that while the plan calls for actions to begin now, once the interim action is completed EPA could decide that additional work may be needed to address any remaining contamination in this portion of the river.

The finalized interim plan calls for:

  • Capping and dredging of approximately 387,000 cubic yards of contaminated sediment that would otherwise have not been addressed until years later when all of EPA’s final study work is completed.
  • Capping source areas of contamination. Prior to capping, sediment will be dredged to a depth to accommodate the cap so that the potential for flooding is not increased.
  • Additional capping and dredging in areas with the potential for erosion and high concentrations of contaminants in the subsurface.
  • Evaluating areas where sediments can be dredged so that capping would not be needed.
  • Processing dredged materials at one or more nearby sediment processing facilities possibly already being used for work further downstream before material is taken off-site for disposal at licensed disposal facilities.
  • Restricting activities in the river to protect the cap, and the continuation of New Jersey’s existing prohibitions on fish and crab consumption.
  • Monitoring and maintaining the cap to ensure its stability and integrity in the long term.

On April 14, 2021, EPA released for public comment the proposed plan describing its multi-phased approach to address contamination for the upper 9 miles of the Lower Passaic River Study Area. EPA held a virtual public meeting on April 27, 2021 to inform the public of EPA’s preferred action and to receive public comments.

The interim action to remove source material is part of the adaptive management approach that EPA is using to reach a final cleanup plan for the Lower Passaic River Study Area.

This means that ongoing sampling will be conducted to gauge the progress of the cleanup and assess the river to determine if more work is needed to meet the goals of a final plan. EPA would propose a final cleanup plan for the entire Lower Passaic River at that time.