Occupational safety and health experts have told the General Services Administration that there is a large amount of potentially carcinogenic asbestos sprayed on exposed ceilings in the Safeway Building, a leased downtown office building occupied by 380 Justice Department employes.

Peter S. Lees, an industrial hygenist from Johns Hopkins University, said GSA and Justice officials were told in a verbal report that extensive testing should take place to determine the extent of the danger.

The officials were also advised that all repair and alterations work on the building should be halted and that GSA should plan to "encapsulate"--fully cover--the ceilings if it plans to continue to lease the facility for Justice, Lees said.

"Right now we are not aware of any dangers to the employes in the buildings," GSA regional health and safety supervisor Peter R. Gillson said. "The tests have all turned up low readings of airborne asbestos. But we recognize the degree of risk if it is disturbed by renovation work ."

Sharp microscopic asbestos fibers become dangerous when they are inhaled and lodge in the lungs.

Located at 521 12th St. NW, the Safeway Building houses part of the Justice Department's antitrust division. GSA learned about the extent of the problem after Lees and colleague Morton Corn were asked to assess the asbestos dangers in the Safeway and nearby Star Building at 1101 Pennsylvania Ave. NW.

Lees said that GSA has been told that there is exposed asbestos on the second through eighth floors of the nine-story building. "As long as the asbestos isn't disturbed, GSA can go about the business of sealing it," Lees said. "Before I come up with a major recommendation for GSA, I'd like to do a more detailed look."

"We will have to encapsulate the ceiling," Gillson said, explaining that orders have been issued to stop repair and alteration work in the building. He said the asbestos was sprayed on years ago as a fire retardant. "Because it was properly applied in most places, it is not friable flaking , but in many places it has not been covered with paint, which makes it susceptible to flaking."

Jerry Rubino, director of security and safety for the Justice Department, said he has issued a memorandum to agency employes urging them to be on the lookout for unauthorized repair work done by Justice, GSA or the building's owners and to report it to his office.

"We don't necessarily have the authority to fix the asbestos problem in the building ourselves; we have to let GSA do that," Rubino said. "But we are going to make sure that it is done and, in the meantime, that no other repair work goes on in the building."

Gillson, however, said that Justice yesterday sent over six requests for repair work--ranging from the installation of an air conditioner to painting--in the Safeway Building.

"We have to decide what we can and can't do so that employe health is not endangered," Gillson said.

The Star building, which has 160 Justice employes, also has an asbestos problem, but Corn and Lees said it is not as serious.

GSA Public Buildings Commissioner Richard O. Haase said all federal workers were supposed to be out of the building by Oct. 1, but because 80 of them were supposed to move to the Safeway building, their move will be delayed until October 1984. Building owners plan a complete renovation of the historic building.