Air samples from the Federal Building in Oak Ridge suggest that no employees were exposed to asbestos from loose insulation that has fallen into heating and cooling ducts, a federal official said Thursday.

“We are pleased with the results,” said Johnathan Sitzlar, supervisory property manager for the U.S. General Services Administration, which owns the building.

GSA and the U.S. Department of Energy, which leases the building, discussed the results with employees during a Thursday afternoon meeting at New Hope Center.

However, the asbestos-containing materials still need to be removed. It’s not clear how much there is, how long it might take, or what it will cost, Sitzlar said.

“It’s rather extensive,” he said.

The five-story, 155,000-square-foot building will remain closed until GSA determines how to remove the loose insulation.

Experts have been called in to help, including industrial hygienists and U.S. Public Health Service.

“We are trying to find the best course,” Sitzlar said.

There about 200 federal employees who work in the building, and a total of 350 personnel, including support service contractors and staff members for U.S. Rep. Chuck Fleischmann.

Some employees are working in the Federal Building’s basement—it uses a different air-handling unit—and many are now stationed at Building 2714-G on Laboratory Road. Some are also at DOE’s Office of Scientific and Technical Information in east Oak Ridge, said Mike Koentop, spokesman for the department’s Oak Ridge Office.

Everybody should be back to work by Monday, he said.

Sitzlar said GSA has many buildings that were built before the late 1970s, and they used materials that contained asbestos.

“This is something that we deal with,” he said.

The Federal Building was shut down Thursday evening after an inspection found asbestos-containing insulation had fallen into heating and cooling units.