A major plutonium plant at the Hanford Nuclear Reservation in Washington state has been put on pause after radioactive contamination spread outside the facility. A radiation monitor alarm sounded Friday while crews were working to contain radioactive contamination on a waste pile. The contamination was found where workers planned to contain it during the demolition. Radiological surveys identified low levels of contamination on workers' protective clothing but no contamination on the clothing they wore underneath or on their skin. Nasal smears also found no evidence of inhaled contamination. Project contractor CH2M Hill Plateau Remediation says the company is investigating how the contamination spread and will take steps to reduce the risk of another incident. Demolition is expected to resume next week.