In 1966, the government paid Dr. Robert E. Carroll to study some health risks of cadmium in the air. He found that it appeared to increase the risk of heart disease.

But to his horror, his own agency - the U.S. Public Health Service's Division of Air Pollution, which later would become part of the Environmental Protection Agency - scattered cadmium sulfide near cities nationwide as part of its pollution studies."I wrote several memos warning of the possible dangers and, if nothing else, the public relations mess that would result if one branch were found to be blowing cadmium over U.S. cities while another was publishing its toxicity," Carroll said.

"The memos were ignored, as far as I can tell," said Carroll, whose warnings continued to be ignored even after he published his findings in the Journal of the American Medical Society in 1966.

Now, 25 years later, Carroll's predictions of a public-relations mess came true for the government - but for a different agency than he expected.

It happened when the Deseret News reported the Army spread cadmium sulfide throughout the East in tests designed by researchers at Dugway Proving Ground to see if it might be possible to spread germ weapons over vast areas.

The Army tests were performed despite decades of studies that said the compound could cause disease of the lung, liver, kidney and heart, and death. The story ran nationwide and created public relations problems for the Army.

But Carroll's story shows the Army wasn't the only government agency spreading sizable amounts of cadmium sulfide over U.S. cities, which the Army had also claimed.

His old agency used it, too, which raises more questions about how much danger the government may have presented to residents nationwide with its use of the chemical.

"I didn't know the Army was also spreading cadmium sulfide, but my boss may have," Carroll said. "I didn't have access to classified material."

Such tests by the Army continued into the 1970s -- long after Carroll's findings were published. The Army finally halted the tests when Dr. L. Arthur Spomer, a former Fort Douglas meteorologist who is now a professor at the University of Illinois, forced an official safety inquiry by pointing out studies such as Carroll's.

The chemical was used because it fluoresces under untraviolet light. Particles on filters can easily be counted to determine how far winds spread the chemical. Scientists say, however, that other less dangerous materials could have been used instead -- but they require somewhat more difficult experiments.

Carroll -- a retired professor and department chairman at the Albany Medical College who now runs a marina on Lake Champlain along the New York-Vermont border -- said that when he worked as chief of the epidemiology section of the Division of Air Pollution, one of his projects was studying the toxicity of cadmium in the air.

"While working on the project and after publishing (results), I was aware that other branches of the agency were using cadmium sulfide for wind-current studies," he said.

He added that from reports he saw, "They would stand on a knoll or hilltop over a city and using a crop-duster-type machine would blow it out over the area. I never watched it. I stayed away from such things -- I saw the studies about its toxicity."

A quarter of a century later, he says he cannot remember for sure what cities were involved in such tests, "but I think St. Louis was one."

He added that officials at his agency "didn't think there was sufficient dosage to matter much." But he said cadmium is poisonous, and extreme care should have been used with it -- which he encouraged through memos at the time.

"I was very upset at the time and made my calculations of dosage to city residents and the workers involved in the release," he said. "As I remember, the dose in community air was relatively small, perhaps doubling the 'normal' ambient amounts for a short time. But (it was) an uncalled for and possible harmful exposure."

He adds that he has no files left from the time, nor access to them, and no copies of the memos that he wrote. The Deseret News, however, has requested copies of reports about the testing he describes through the Freedom of Information Act.

The Army has also refused portions of similar FOIA requests for information about how much cadmium sulfide it dropped from airplanes, from what altitude and what concentrations were observed. Such information is needed to determine how dangerous it may have been.

The Army said it would endanger national security. The tests were to determine whether germ weapons could be spread over large areas throughout the nation.

The Deseret News has appealed such refusals. Rep. Wayne Owens, D-Utah, is organizing a congressional effort to seek such information. And Sen. John Glenn, D-Ohio, is considering whether his Senate Government Operations Committee should hold hearings or order investigations into the government's use of the chemical.

Mike Yeagar, an Owens' aide organizing the effort to obtain more information about cadmium sulfide testing, said Carroll's additional revelations are "amazing" and give additional reason for a possible congressional investigation about use of the chemical.