MassDEP Upheld Denial of Holtec Wastewater Discharge
The state environmental agency rejected an appeal to release treated reactor water into Cape Cod Bay.
Updated on Sept. 18, 2026 in Nuclear
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The Massachusetts Department of Environmental Protection has dismissed an appeal from Holtec International regarding the disposal of 1.1 million gallons of wastewater. The agency maintained that discharging the water into Cape Cod Bay would violate the Ocean Sanctuaries Act.
Why it matters
The decision protects the environmental integrity of the local sanctuary by preventing the release of industrial waste. It reinforces state regulatory authority over nuclear decommissioning projects within sensitive coastal areas.
MassDEP reviewed over 1,000 public comments and held three days of evidentiary hearings before reaching this conclusion. The plant site currently holds 1.1 million gallons of water related to former reactor cooling operations.
The players
Massachusetts Department of Environmental Protection
This is the state agency responsible for protecting human health and the environment by ensuring clean air, land, and water.
Holtec International
This company is a global supplier of equipment and services to the nuclear power industry and manages decommissioning projects.
Bonnie Heiple
She serves as the Commissioner of the Massachusetts Department of Environmental Protection.
The details
Commissioner Bonnie Heiple dismissed the appeal after the agency classified the material as industrial wastewater, which is strictly prohibited under the Ocean Sanctuaries Act. Holtec International, which is managing the decommissioning of the site in Plymouth, now faces further limitations on its disposal options.
Timeline
May 2019: Pilgrim Nuclear Power Station ceased electricity generation.
July 18, 2024: MassDEP initially denied the discharge application.
August 16, 2024: Holtec appealed the initial permit denial.
November 2025: OADR issued a recommended decision to the Commissioner.
2034: Scheduled completion of site decommissioning.
The Big Picture
This ruling reinforces the long-standing regulatory framework provided by the Ocean Sanctuaries Act. It maintains a strict legal precedent that prevents the classification of nuclear-related wastewater as anything other than industrial waste in protected waters.
Residents in the Cape Cod area will not see the discharge of treated cooling water into local bays, potentially mitigating concerns over water quality. The decision ensures the current status quo remains while Holtec continues its decommissioning process through 2034.
The takeaway
The state's refusal to permit the discharge highlights the ongoing tension between nuclear site decommissioning and local environmental protections. Holtec may still pursue further legal action through the Massachusetts Superior Court to challenge this final administrative decision.
Further reading
Learn more about local environmental oversight in the Nuclear section.
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Should private companies be permitted to discharge treated industrial waste into protected local waters?
