Officials in Minnesota are monitoring the cleanup of a massive spill of radioactive water from a nuclear power plant just outside Minneapolis. About 1.5 million litres (400,000 gallons) of nuclear wastewater leaked from the plant back in late November, but the incident wasn’t made public until Thursday. Xcel Energy, the company that operates the affected nuclear power plant, promises that the spill poses no risk to public safety, as did the Minnesota Pollution Control Agency.