Radioactive water was discharged into New York’s Hudson River for more than 60 years, with millions of gallons released annually during its decades of operation.

The long-running practice at the now-defunct Indian Point nuclear plant is drawing renewed scrutiny after a 2025 court approved a controversial plan to release an additional 45,000 gallons of radioactive water per year from the shuttered facility.

The Daily Mail has uncovered a 1970 federal investigation showing the plant discharged an average of two to three million gallons of processed wastewater each year between 1962 and 2021, including treated radioactive effluents.

The probe into the plant’s environmental impact found that millions of fish were killed during its early years, largely after being pulled into the facility’s cooling system.

Investigators also documented chemical discharges that exceeded state safety limits and warned that gaps in monitoring made it impossible to rule out toxic releases that may have contributed to fish kills.

Testing conducted near the plant further detected measurable increases in radioactivity in water, sediment, vegetation and fish closest to discharge areas.

The findings, combined with a newly circulated stakeholder letter from the plant's current owner, Holtec International, confirming decades of releases, have intensified concerns about the long-term environmental impact on the Hudson River.

Patrick O’Brien, director of government affairs and communications for Holtec International, which purchased the plant in 2021, told the Daily Mail: 'I can’t speak to operations, since that covers previous owners to the '60s.'

'During our ownership, no releases have occurred exceeding federal limits, and every batch is tested and reviewed prior to dilution and discharge.'

The Indian Point nuclear power plant is located along the Hudson River just south of Peekskill. Holtec International purchased the facility shortly after its closure and now oversees its decommissioning, including the handling of stored wastewater and spent nuclear fuel.

A recently circulated letter to stakeholders confirmed that treated radioactive wastewater had been discharged into the Hudson River since the plant’s earliest years, with annual environmental and radiation reports submitted to federal regulators.

Those records indicate that radioactive materials, including tritium and other radionuclides, were diluted and released into the river following treatment processes designed to remove most contaminants before discharge.

Federal investigators first examined concerns about the plant’s environmental impact decades ago, launching a detailed study in 1970 amid growing public alarm about the effects of nuclear facilities along the Hudson River.

While the investigation found no clear evidence that radioactive releases alone caused widespread ecosystem collapse, it documented significant environmental impacts tied to plant operations.

Among the most notable findings was the death of large numbers of fish during the plant’s early years.

Between 1962 and 1970, officials estimated that between 1.5 million and five million fish were killed after becoming trapped against intake screens used to draw cooling water from the river.

The report also warned that fish eggs, larvae and other small aquatic organisms were likely harmed as they passed through the plant’s cooling systems. 

Investigators determined that structural features near intake areas may have worsened the problem by attracting fish seeking shelter, increasing their risk of being pulled into the facility.

Beyond mechanical fish deaths, officials raised concerns about the handling of industrial chemicals used within the plant.

Records showed that several chemical discharges exceeded state safety limits, including multiple incidents involving chlorine releases.

In three documented cases in 1967, state chlorine limits surpassed allowable thresholds for periods ranging from approximately 15 minutes to one hour.

Although those exceedances were limited in duration, investigators warned that incomplete monitoring records prevented officials from confirming whether similar events occurred at other times.

The report further stated that gaps in historical monitoring left uncertainty about the full scope of chemical releases into the Hudson River.

Investigators acknowledged that sudden releases of toxic substances, particularly during accidents or operational disruptions, could not be ruled out and may have contributed to localized fish kills.

Researchers also confirmed that radioactive materials were released into the river during normal operations.

Sampling conducted near the plant detected measurable increases in radioactivity levels in nearby water, sediment, vegetation and fish, particularly in areas closest to discharge points.

Although these increases were described as relatively small compared with natural background radiation levels, investigators noted uncertainty in estimating long-term exposure risks to aquatic life.

Officials also warned that the combined effects of chemical discharges, temperature changes and radioactive materials were not fully understood at the time.

The interaction of these factors, particularly during sudden release events, could have created localized environmental stress that was difficult to measure using available monitoring methods.

Despite these concerns, the report ultimately concluded that widespread, irreversible damage to the Hudson River ecosystem was not definitively proven.

However, investigators stated that documented fish deaths, chemical exceedances and monitoring gaps demonstrated measurable harm in certain areas and left open the possibility that additional impacts may have occurred.

Holtec has maintained that all wastewater releases conducted under its oversight have remained within federal regulatory limits.

The company emphasized that each batch of wastewater is tested and reviewed before discharge and that any material failing to meet regulatory standards is reprocessed before release.

Federal records filed with regulators indicate that radiation exposure levels recorded between 2005 and 2019 remained well below federal safety thresholds.

Still, critics argue that the cumulative impact of decades of releases — combined with the newly approved plan to discharge additional wastewater — raises ongoing concerns about the long-term health of the Hudson River ecosystem.

Environmental advocates have pointed to the plant’s long history of fish deaths, chemical exceedances and incomplete monitoring records as evidence that the full environmental impact may never be completely understood.

The renewed debate comes as the Hudson River continues to recover from decades of industrial pollution, with restoration efforts aimed at rebuilding fish populations and improving water quality.

With additional wastewater releases planned in the coming years, regulators and environmental groups are expected to closely monitor future discharges and their potential impact on one of New York’s most historically significant waterways.