A radioactive material has been detected in the groundwater below a nuclear power plant north of New York City. Gov. Andrew Cuomo said Saturday that water contaminated by tritium leaked into the groundwater at the Indian Point Energy Center in Buchanan, 40 miles north of Manhattan. Officials say the contamination has remained contained to the site and there's no risk to the public. Cuomo says the state's environmental conservation and health departments will investigate. Elevated levels of tritium were found in two monitoring wells at the plant in 2014. Officials said then the contamination likely stemmed from an earlier maintenance shutdown. (More radioactive leaks stories.)