For four months in 1969, the Army sprayed a swampy forest on Maryland's Eastern Shore with flourescent particles in an effort to gauge the extent of fallout in chemical and biological warfare, according to government documents.

Residents were told only that their land would be used for a "government project" which, according to the documents, involved "open air" spraying of the chemical zinc cadmium sulfide. The chemical, whose immediate and long term effects on humans are in dispute, was sprayed 115 times from Aug. 1 to Nov. 24, 1969.

"All they told me was it was a governmental test," said Ralph Asplen, now a retired farmer who rented a nine-room house to participating scientists. "I didn't figure it was any of my business."

"I'm looking right at the area out my window right now," said State Sen. Frederick C. Malkus (D-DORCHESTER), "but as far as I knew, the only chemical warefare we've had down here was on the damn mosquitos."

The testing program was disclosed in documents obtained through a freedom of information request by the Church of Scientology, which, among its many other pursuits, has been fighting proposals for renewed chemical and biological warfare research.

Other documents obtained by the Scientologists in recent months have revealed a whole series of similar tests that were conducted in the 1950s and 1960s in places such as Fort Wayne, Ind., Dallas and Fort Worth, Tex. and Norfolk. Earlier documents showed that similar tests were conducted in 1953 in Frederick County, Md., and Loudoun County, Va.

In several instances, the government used a chemical that Pentagon spokesman Maj. Leon T. DeLorme said yesterday only "simulated" a substance intended for possible military use. The chemical, he said, is "like dust" and "would have no impact on you."

Dr. L. Arthur Spomer, formerly assigned to the Chemical Warfare Corps at the Army's Dugway Proving Ground in Utah and now a horticulture professor at the University of Illinois, has disagreed with that assessment, however. Writing in a professional journal in 1972 and during more recent interviews, Spomer has said the use of the chemical compound in atmospheric tests presents "a potential human health hazard."

"Even brief exposure to high concentrations may result in pulmonary edema and death," Spomer wrote.

"Water is potentially harmful," countered DeLorme. "If you ingest enough water, it will kill you."

The latest documents do not detail the quantities used on the Eastern Shore. The sparsely settled site 12 miles southwest of Cambridge was chosen for the testing program after two other locations in Northern Virginia were rejected, in one case due to "public concern for the integrity of the bald eagle nesting area," a "final report" on the program said.

The two Virginia locations were Mason Neck in southeastern Fairfax County and the Conway Robinson Memorial Forest, 16 miles from the Falls Church laboratory that produced the chemical. The Eastern Shore site, in Dorchester County's Green Briar Swamp, was described as an "excellent experimental ground" because of its flat terrain and "mature, temperate, deciduous stand" of trees.

Explaining the choice, the 1970 report said, "A bomb bursting in a tropical jungle will give quite different sizes and shapes of dosage contours, and different rates of dosage buildup, than will a similar bomb in temperate grassland. These differences need to be known for all potential operational areas, for prediction of weapons effects and defensive requirements."

During the Dorchester testing, four local residents were hired to stand guard at the Green Briar site and the chemical manufacturer hosted a party for the citizens. A tower was erected in the middle of the swamp, and air samples were collected at various points and sent by registered mail to the Army's Desert Testing Center in Utah, for further examination.

The day after the final test in the series, President Richard M. Nixon ended such programs, saying the United States henceforth would limit its biological research "to defensive measures such as immunization and safety."

William Wingate, the current president of the Dorchester County commissioners, said yesterday he lacked sufficient information to react to the report.

"I still got a little bit of confidence in Uncle Sam," he said, adding, "Of course, sometimes it's kind of shaken."