Leaking air-conditioner refrigerant resulted in the evacuation this morning of workers at the Kaiser Permanente administrative offices at 711 Kapiolani Boulevard.

Firefighters were sent to the building about 7:20 a.m. in response to a report of smoke in the building.

A light gray haze was visible inside the building's lobby at 7:30 a.m. as dozens of office workers waited on the sidewalk outside while firefighters searched for the source of the problem.

Stu Glauberman, a Kaiser spokesman, said later that the smoke was actually refrigerant that had leaked from the building's air conditioning system.

Employees were allowed to return to the building about 8:45 a.m., Glauberman said. Some of them, who work in the patient accounting office, where the problem seemed to originate, were released for the day.

Firefighters from the hazardous materials unit were called to the building about 8:45 to further evaluate the situation.

Fire Capt. Terry Seelig said tests showed the leaking gas was "an older Freon type."

There were no reports of injury or "medical distress" among the employees, Seelig said.