The federal agency that regulates nuclear power plants is sending an inspector to pore over Westchester County's Indian Point plant after a spill leaked radioactive water into groundwater around the plant. The Nuclear Regulatory Commission prober will join investigators from the state Health Department and Department of Environmental Conservation looking into the cause of the spill that elevated levels of tritium in at least 3 of 40 wells at the facility. Governor Andrew Cuomo, who has repeatedly called for the plant to be closed, said the contamination was "alarming" and "unacceptable," but acknowledged that it is below federal safety limits.

"This is not the first such release of radioactive water at Indian Point, nor is this the first time that Indian Point has experienced significant failure in its operation and maintenance," Cuomo said in a statement. "This failure continues to demonstrate that Indian Point cannot continue to operate in a manner that is protective of public health and the environment."

Cuomo, federal officials, and Indian Point operator Entergy have all emphasized that the radiation currently poses no known threat to workers or nearby residents. In a statement, Entergy wrote:

While elevated tritium in the ground onsite is not in accordance with our standards, there is no health or safety consequence to the public, and releases are more than a thousand times below federal permissible limits. The tritium did not affect any source of drinking water onsite or offsite.

Neil Sheehan, spokesman for the Nuclear Regulatory Commission, told reporters that the inspector would join NRC regulators permanently stationed there to analyze the leakage as well as Entergy's response.

Environmental activists have long demanded the government close the plant, noting that it sits near two fault lines and that more than 20 million people live within 50 miles of it. The plant is just more than 30 miles north of the Bronx border and its oldest reactor is more than 50 years old. Transformer fires and other mishaps have taken parts of it offline several times in the last year, as Riverkeeper president Paul Gallay noted to the Daily News.

"The next one could be a catastrophe," Gallay said. "The stakes are just too high."

This isn't the first time the plant has leaked radioactive water, either. The News wrote:

A federal oversight agency issued a report after about 100,000 gallons of tritium-tainted water entered the groundwater supply in 2009, and elevated levels of tritium also were found in two monitoring wells at the plant in 2014.

Last month, Entergy sued the state over Secretary of State Cesar Perales trying to block the renewal of Indian Point's federal license by denying it a coastal safety certification it needs to renew with the feds. Perales's letter denying the approval cited the risk of earthquakes, the surrounding population density, the plant's proximity to the source of drinking water for much of the New York metro area, and the plant's killing of more than a billion fish in the Hudson River over the last four decades. In its suit, the utility giant argues that the state is overstepping its bounds in trying to regulate nuclear safety, a federal function, and that Perales's and Cuomo's arguments run contrary to their acceptance of the state's three other nuclear plants.

Entergy spokesman Jerry Nappi told the News that Westchester's burbling nuclear neighbor works fine, most of the time.

"Indian Point is online an average of more than 90% of the time, reliably providing electricity for about 2 million residences in New York City and Westchester County," he said.