District government officials have tentatively traced the mysterious green substance that descended on Foggy Bottom recently to emissions from a federal heating plant in nearby Georgetown.

Laboratory tests showed that "the material we collected in Foggy Bottom has the same analytical pattern - the same footprints - as the discharges from the West Heating Plant of the General Services Administration," Dr. Bailus Walker Jr., director of the city's Environmental Health Administration, said yesterday.

A GSA official acknowledged that "deviations from normal operating procedures" had caused unusual discharges during the period when the mysterious substance appeared. "We don't think we're the cause," said Kenneth F. Ward, manager of heating operations and transmission for GSA's Region 3. "But if we are, why, we are."

"Actions have been implemented to prevent a recurrence," Ward said.

The incident apparently was not reported by plant personnel to GSA supervisors, nor to the D.C. government. "Appropriate action is going to be taken against certain people," Ward promised.

Foggy Bottom residents first reported the mysterious substance on Sept. 6. The substance later was blamed for killing plants and flowers, making pets ill, and leaving a green or black film on cars and other exposed surfaces.

The GSA heating plant, which serves federal buildings throughout much of downtown Washington, is located immediately north of the Whitehurst Freeway and west of Rock Creek Park.

Ward said the unusual discharges had occurred after a breakdown in a vacuum system that helps remove soot from the plant's firing chamber. When employes tried to remove the soot manually, it shot up through smokestacks into the air, Ward said.

D.C. officials have identified the substance's principal components as nickel sulfate, iron sulfate, manganese and vanadium. Ward said yesterday he was still studying the question of whether all those materials could have come from the GSA plant.

Meanwhile, Jerry Oaks of 953 26th St. NW, in Foggy Bottom, reported that his cat Sweetie, which apparently had eaten grass exposed to the substance, remained firm in her refusal to eat.

"I've been forcing vitamin drops down her throat," said Oaks. "But I don't know what's keeping her alive."