Updated at noon Thursday

SPOKANE -- A take-cover order for about 350 workers at a former plutonium production plant in Washington state has been lifted after low levels of radiation were detected.

The workers had been ordered to go inside a building after alarms sounded about 7 a.m. Thursday at the Hanford Nuclear Reservation.

That order was lifted about four hours later.

The Energy Department said no injuries have been reported at the site near Richland, Washington, where the government for decades made plutonium for nuclear weapons.

Officials for Hanford said low levels of contamination were found outside the Plutonium Finishing Plant, including locations on sidewalks and near a vehicle access gate.

The Department of Energy said workers applied an adhesive product to the contamination to prevent it from spreading.

It was not immediately clear if employees went back to work. No other details were provided.

Hanford made about two-thirds of the plutonium for the nation's nuclear arsenal, and is now engaged in cleaning up the huge volume of resulting radioactive wastes.

-- The Associated Press