Radioactive material has leaked into the groundwater below a nuclear power plant north of New York City, prompting a state investigation on Saturday and condemnation from governor Andrew Cuomo.

Cuomo ordered an investigation into “alarming levels of radioactivity” found at three monitoring wells at the Indian Point energy center in Buchanan, New York, about 40 miles north of Manhattan.

“Our first concern is for the health and safety of the residents close to the facility and ensuring the groundwater leak does not pose a threat,” Cuomo wrote in a letter that directed health and environmental officials to investigate.

In one location radioactivity levels rose nearly 65,000%, from 12,300 picocuries per liter to over 8,000,000 picocuries per liter. The Environmental Protection Agency’s maximum contaminant level for tritium in drinking water is 20,000 picocuries per liter, though Entergy, the company that owns the plant, emphasized that only groundwater, and not drinking water, were contaminated.

The governor’s office said the contamination had not moved offsite. Cuomo has encouraged Entergy to shut down Indian Point, but to keep its other plants further upstate open.

He directed health and environmental officials “to determine the extent of the release, its likely duration, cause and potential impacts to the environment and public health”.

“While elevated tritium in the ground onsite is not in accordance with our standards, there is no health or safety consequence to the public,” Entergy said in a statement released late Saturday. “Releases are more than a thousand times below federal permissible limits. The tritium did not affect any source of drinking water onsite or offsite.”

The plant supplies roughly 30% of the electricity consumed by New York City. Indian Point had three emergency shutdowns in December, prompting the governor’s office to launch, and then expand, an inquiry into operations and safety standards at the facility.

There have been many tritium leaks at the plant in recent years, though Saturday’s leak appears to be the most serious so far. Public service commission chair Audrey Zibelman faces a deadline for the results of the pre-existing investigation by President’s Day, 15 February.

“This latest failure at Indian Point is unacceptable,” Cuomo said in a statement. “This is not the first such release of radioactive water at Indian Point,” he said, adding: “this failure continues to demonstrate that Indian Point cannot continue to operate in a manner that is protective of public health and the environment.”

Tritium is a radioactive hydrogen isotope that cannot penetrate the skin; however, it is considered a health risk for illnesses, including cancer.



The governor’s office did not immediately respond to request for further comment on the beginning of the leak and its duration.