All six floors of the Commerce Department except the basement will reopen today, allowing 3,700 federal employees to go back to work after a fire on Friday caused the release of small amounts of a cancer-causing liquid and forced the evacuation of the building, officials said yesterday.

Commerce Department spokesman Morrie Goodman said the basement of the 14th Street NW building--where the fire was caused by an explosion that also released polychlorinated biphenyls, or PCBs--will remain closed for at least another day.

Crews were continuing to clean up debris and material used to put out the fire, Goodman said. Fewer than 200 employees work in the basement, which houses a travel agency, credit union and cleaning company.

All employees, except those who normally report to work in the basement, should return to their regular workplace today, Goodman said. People who work in the basement should report to the auditorium or check with supervisors.

A day-care center on the building's first floor will reopen as scheduled today, as will the National Aquarium, Goodman said. The underground parking garage will be open, though those who use the garage will have to exit via the ramp and enter the building through an outside entrance, Goodman said.

"Everything, if it's not in the basement, will be open," he said.

Environmental, safety and building specialists from the General Services Administration cleared the building for reopening late yesterday, and officials said there is no health or safety risk to employees. The D.C. Fire Department, which responded to the emergency on Friday, turned the matter over to the Commerce Department and GSA for the safety checks.

"This was not a casual follow-up to Friday," Goodman said, adding that top Commerce officials were consulted throughout the day yesterday. "We want people to be assured and reassured that the building is safe."

The explosion occurred at 6:15 a.m. Friday in the basement of the 1.6 million-square-foot structure. It was caused by malfunctioning equipment that runs the building's clocks. Several canister-type devices--each slightly larger than a television remote-control unit--are housed in large electrical boxes. Each canister contains about two ounces of oil; it is that oil that contained the PCBs, officials said.

Two of the electrical boxes burned; each box contains four canisters. The fire was mostly contained in the boxes, but some of the oil dripped out, they said.

After some employees became ill Friday, firefighters learned that the equipment contained toxic material. Forty-eight people, including 10 firefighters, were taken to George Washington University Hospital for decontamination. All were released Friday.

Employees with questions about the building's reopening may call 202-482-2000.