Massachusetts environmental regulators have delivered a final blow to Holtec International's yearslong push to dump more than a million gallons of treated nuclear wastewater from the shuttered Pilgrim Nuclear Power Station into Cape Cod Bay. On Tuesday, the Massachusetts Department of Environmental Protection officially upheld its earlier denial of the discharge, closing out the state's internal appeal process in a fight that has drawn more than 1,000 public comments and organized local opposition.
MassDEP Commissioner Bonnie Heiple was responsible for finalizing the decision after a recommendation from Presiding Officer Salvatore Giorlandino of the Office of Appeals and Dispute Resolution, according to a Massachusetts Department of Environmental Protection announcement. Giorlandino's recommendation, announced November 7, 2025, followed a two-day evidentiary hearing, capping a process that also included a public hearing and review of more than 1,000 public comments, as reported by MassLive.
Holtec, which oversees decommissioning of the Plymouth plant, had appealed MassDEP's July 2024 decision denying permission to discharge up to 1.1 million gallons of treated wastewater directly into the bay. MassDEP determined the proposed release would constitute industrial wastewater, and that Cape Cod Bay's status as a state-designated ocean sanctuary made the discharge illegal under the Massachusetts Ocean Sanctuaries Act, which bars commercial, municipal, or industrial waste from entering protected sanctuaries, per MassLive's report.
Holtec's Legal Arguments Rejected Point by Point
In its administrative appeal filed in August 2024, Holtec argued that its discharge was grandfathered in before the Ocean Sanctuaries Act took effect, that it was tied to power generation, and that federal law preempted the state's authority altogether, according to CAI. The recommendation called for upholding the denial and addressed Holtec's exemption and preemption arguments, according to the same report.
The law placed Cape Cod Bay under statutory protections barring new industrial waste discharges into state ocean waters, making it one of the state's ocean sanctuaries, per the Massachusetts Department of Environmental Protection. The dispute also involved Holtec's preemption arguments.
Wastewater Keeps Evaporating While the Fight Drags On
Even as the discharge permit remains dead, the wastewater itself hasn't gone anywhere in the traditional sense — much of it has simply evaporated. The total volume of treated wastewater stored at the Pilgrim site fell from more than 1.1 million gallons in 2022 to under 800,000 gallons by May 2026, according to a report from NENC. That decline has come through ongoing natural evaporation on site, a process that continues under air-quality limits while the surface water discharge dispute plays out.
MassDEP determined back in July 2024 that Holtec doesn't need a state air quality permit to evaporate the wastewater, since non-radiological air emissions are minimal and radiological air emissions fall exclusively under federal Nuclear Regulatory Commission jurisdiction, according to the Plymouth Independent. In effect, while state law prohibits Holtec from putting the wastewater into the bay, state regulators have no authority to stop it from rising into the air instead — a gap that has frustrated local advocates pushing for the water to be trucked offsite entirely.
The $20 Million Alternative
Trucking the wastewater away has never been cheap. In 2022 internal evaluations, Holtec estimated that packaging and shipping the full 1.1 million gallons to a licensed out-of-state waste facility in Texas would cost roughly $20 million, according to reporting cited by the Plymouth Independent. Environmental advocates have urged Holtec to pursue offsite transport rather than rely on local discharge or atmospheric evaporation.
Pilgrim Nuclear Power Station began operations in Plymouth in 1972 before it shut down permanently in 2019. The transaction transferring ownership from Entergy to Holtec International was finalized on August 26, 2019, according to Holtec International's own account of the project.
Broad Local Opposition and What Comes Next
The fight over the bay's future drew a wide coalition of local opposition. Nineteen community organizations, local government entities, and advocacy groups led by the Association to Preserve Cape Cod intervened in MassDEP's administrative appeal to back the state's prohibition on ocean discharge, according to the Association for Preserve Cape Cod. The opposition included fishing and tourist interests.
With MassDEP's administrative process now complete, Holtec retains the legal right under state procedure to appeal the permit rejection to Massachusetts Superior Court, according to the Massachusetts Department of Environmental Protection. Such an appeal would move the matter from agency proceedings into the state judicial system.
