Deadly gas poured out of a CIA building in downtown Washington yesterday morning, hospitalizing seven persons, after a fire began in an electrical circuitry box in the building.

Two firemen, two building security guards and three persons who works in the building at 1724 F st. NW, were overcome by polyvinyl chloride fumes that were released from melting plastice wire coverings throughout the building.

Firemen had to request two ladder trucks that were used to open windows in the building and doors on the roof of the building, according to Harry Gates, deputy chief of the D.C. Fire Department.

Gates said the six-story brick building was not severely damaged by the fire which began at 9:17 a.m. yesterday.

Gates said no papers or furniture in the building were damaged by the fire. He said he did not know what the building was used for by the CIA.

Spokesmen for the CIA did not return a reporter's telephone calls yesterday.

"The main problem was getting people out of there," Gates said. "It is a deadly gas concentration and it's colorless. You don't know what it is until you reach the point where you can't breath" he said.

Gates said two of the firemen were overcome by the gas, despite wearing gas masks. The firemen were identified as William Smith and Thomas Brewer. They were released from Washington Hospital Center after receiving treatment.

Guards and workers at the building were treated at George Washington Hospital and released, the hospital reported. The hospital said three additional workers came to the emergency room after five had been brought there by ambulance.

Gates said the fire was caused by short-circuit of an electrical overload. He said firemen used carbon dioxide extinguishers to put out the blaze, which lasted about an hour.