OAK RIDGE, Tenn. (AP) _ Federal officials who concealed evidence of mercury spills at the government's nuclear weapons parts plant here committed no crime, the U.S. Justice Department has concluded.

After considering the case since October 1983 following an investigation by the Department of Energy inspector general's office, the Justice Departmet found no grounds for prosecution, said Mike Kopp, an aide to Sen. Albert Gore Jr., D-Tenn.

The case now goes back to the inspector general's office to determine whether administrative action will be taken against Oak Ridge officials who handled the case, Kopp said Tuesday.

About 2.4 million pounds of toxic mercury was lost in spills, leaks and mishandling at the Y-12 nuclear parts plant between 1950 and 1977.

The losses were detailed in a 1977 Union Carbide Corp. report declassified by the Energy Department two years ago. Union Carbide operated the plant for the government during that time. The facility is now managed by Martin Marietta Corp.

Shortly after the report's release in 1983, officials began investigating charges of a cover-up by federal officials.

The Justice Department also found no proof that a research biologist who lost his job after studying mercury levels in a creek near the plant was illegally fired from the Oak Ridge National Laboratory, Kopp said.

Steve Gough, 34, claimed officials at the lab tried to hide his 1981 studies which showed high mercury levels in the East Fork Poplar Creek.

About 475,000 pounds of mercury was spilled into the creek which runs from the plant through the city.