A tiny amount of deadly plutonium was accidentally incinerated at an original Knolls Atomic Power Laboratory site in the 1940's and may have contaminated the residential neighborhood, a state Health Department report says.

And two explosions also in the 1940's may have released unkown quantities of plutonium and uranium at the 123 Peck St. site, which was later used for nearly 20 years as a food distribution warehouse, the report said.

In what is apparently KAPL's first public acknowledgement of the incidents, "KAPL staff stated that (between 1947-49), several incidents occurred which could have resulted in the contamination of the building and the nearby environment, " the report said.

The 10-page report was released yesterday as federal and state inspectors returned to the former KAPL site to conduct additional testing for radioactive contamination. Results of an initial survey in July are contained in yesterday's report.

State and federal officials have said the contamination poses no immediate health hazard, but have been unable to assess the potential damage over the past 10 years without further investigation.

"They agreed all along there needed to be more investigation because this initial report doesn't describe the extent of the problem." Health Department spokesman Peter Slocum said , "It's to get a fuller picture of the radiation in the area."

Slocum said the inspectors from the Health Department, Department of Environmental Conservation and the U.S. Department of Energy wanted to extract soil under the Freedom of Information Act samples from homeowners' property near the building.

"There appears to be the potential for contamination off the site and we'd like to define the extent of contamination." Slocum said, "If it's off site, what kind of levels are off site?"

KAPL run by General Electric Co. for the DOE, occupied th 70,000 square foot building from 1945-55 while moving in phases to River Road in Niskayuna in th 1950's. The contamination was left despite an extensive cleanup described in a 1979 document obtained by the Schenectady Gazette under the Freedom of Information Act .

Work there included dveloping a nuclear reactor and chemically separating valuable uranium and plutonium from spent fuel - a radiologically messy process continued in Niskayuna between 1951-54. The separation plant in Niskayuna is scheduled for a $100 million cleanup in the late 1990's.

The bulding was sold to Schenectady Buy-Rite Foods in 1960, which used it as a food warehouse until the late 1970's - a use criticized recently as "plain idiotic" by the Government Accountability Project, which has begun investigating allegations of environmental contamination and worker exposure to radiation at KAPL.

The building is now home to Universal Custom Millwork and Universal Steel Fabricators, owned by Robert Chapman, who requested the surveys this summer.

The inspectors took nine soil samples at the site in mid-July and used Geiger counters inside the building. The report concludes that "available data from the initial sample and survey results do not indicate an immediate health threat to employees or residents."

Of the nine samples, two show uranium contamination above state limits.

The contamination is consistent with that in a sample taken in September by the Government Accountability Project, a Washington, D.C., public interest group. The GAP sample, taken along a bikepath off the property, showed 1,169 picocuries per gram of natural uranium - seven times the state standard of 167 picocuries. A picocurie is a measure of radioactivity.

Contamination detected by Geiger counters inside and outside of the building showed patches of contamination up to1,000 times over natural background. The Geiger counter's highest reading was 50,000 counts per minute on the ground outside a door. Natural background is between 5,000 and 6,000 counts per minute.

KAPL spokesman Gerald Sabian last week said "a current-day radiological survey using state-of-the-art equipment is likely to detect localized , low-level of radioactive materials which would not constitute a health or evironmental hazards."

Sabian said last night he was unable to comment on the documention and two explosives, which were noted briefly in the report:

-On Oct. 7, 1947, a centrifuge tube broke and relased about 500 micrograms of plutonium. About 200 micrograms were inadvertently discarded as trash and burned, in separate incinerations of 100 micrograms, the report says.

Plutonium, a byproduct of splitting uranium atoms, is the most toxic substance known to man. Minute particles can be inhaled, remain in the lungs and bones and cause cancer.

Slocum said he could not assess the hazard of burning 200 micrograms of plutonium. A microgram is one-millionth of a gram. Other Health Department radiological health experts could not be reached late yesterday for comment.

The radioactivity in 200 micrograms is 12.4 microcuries, or 12.4 million picocuries, said Frank Bordell, a former KAPL health physicist. Bordell said the release is significant, but its potential health impact is difficult to judge because of weather, wind and other factors.

In contrast, a soil sample taken near the site showed 1,169 picocuries per gram of uranium, which is less toxic than plutonium.

-In July 1948, an explosion in a chemistry laboratory "may have resulted in the release of plutonium. Records do not indicate cleanup or release estimates," the report says. It does not indicate if the release may have been contained within the building or was released into the environment.

-In June 1949, a natural uranium power explosion occurred in a machine shop "Contamination or release estimates are unknown," the report said.

--A 55 gallon drum containing liquid radioactive waste leaked in a storage building next to the main building, the report said. Additional details were not contained in the report.

City Councilman Frank Duci, who lives near the site, called for an epidemiological survey to determine whether a high incidence of cancer exists among neighborhood residents.

"I think it would be productive." Duci said, "I've lived here all my life and I didn't know the impact a plant like that could have on the community if there were explosions.