State regulators have denied an appeal by Holtec Decommissioning International seeking permission to discharge treated waste water from the former Pilgrim nuclear plant into Cape Cod Bay. The Massachusetts Department of Environmental Protection (MassDEP) upheld its 2024 ruling that barred the release of up to 1.1 million gallons of treated industrial waste water into the protected ocean sanctuary.
Holtec, the company managing the decommissioning of Pilgrim, submitted the appeal to MassDEP’s Office of Appeals and Dispute Resolution after the initial denial in July 2024. Chief presiding officer Salvatore Giorlandino ruled in favor of the state agency in November 2025, affirming that the water proposed for discharge meets the definition of industrial waste and falls under the Ocean Sanctuaries Act’s prohibition on dumping industrial wastes into designated marine areas.
The Pilgrim nuclear plant, located near Plymouth, Massachusetts, ceased operations in May 2019. Since then, Holtec has been overseeing the cleanup of the site, which includes managing large volumes of waste water stored at the facility. The company requested approval last year to release treated water stored at the site into Cape Cod Bay, asserting that the discharge would comply with environmental standards and not pose a threat to the bay’s ecosystem.
Holtec representatives argued that the plant had historically discharged water into the bay during its operational years, which spanned more than four decades. The company also maintained that the proposed discharge would continue that longstanding practice, with the waste water treated to meet applicable pollution standards. As of November 2025, approximately 860,000 gallons of such water remained onsite, containing both radioactive and non-radioactive contaminants.
However, MassDEP rejected Holtec’s request following a public hearing and extensive review of over 1,000 public comments, determining that the discharge would violate state law protecting ocean sanctuaries. The agency emphasized that the Ocean Sanctuaries Act bans discharges of commercial, municipal, domestic, or industrial wastes into designated ocean sanctuaries like Cape Cod Bay.
In a statement, Patrick O’Brien, Holtec’s director of government affairs and communications, said the company is assessing the ruling and evaluating its options, which may include further appeals. He noted that Holtec’s intent has been to safely decommission the site for future use and acknowledged that the ongoing disputes over waste water discharge have delayed their original timeline for completing cleanup within eight years.
The decision represents a significant hurdle for Holtec in managing the environmental legacy of Pilgrim, highlighting the challenges involved in safely closing nuclear facilities while adhering to stringent state environmental protections.