Revealing that the Army spread clouds of a toxic chemical over most of the country to test methods of dispersing germ weapons was an eye-catching story for the Deseret News this week.

But an even better story - and one much more important - is locked away in documents that the Army refuses to release.They contain data that would tell exactly how dangerous those tests were - which the public does not now know.

After the Deseret News made a request through the Freedom of Information Act for Army reports about "Operation LAC" - with the LAC standing for "large area coverage" - the Army turned over 503 pages of information.

But 163 of those pages were completely censored - with only the top and bottom of the page intact and everything else cut away by scissors. Another 60 pages were partially censored.

In short, the Army censored about 40 percent of its reports on Operation LAC before releasing them. That makes piecing the story together somewhat like figuring out what the picture is on a jigsaw puzzle with only 60 percent of its pieces.

But the part of the picture that emerged from what the Army did release included that germ warfare researchers from Dugway Proving Ground designed four tests in 1957 and 1958 that dropped cadmium sulfide over most states east of the Rockies.

They wanted to see if strong winds from the Arctic could spread particles across a continent maybe, for example, to spread wheat stem rust spores that could destroy an enemy's wheat crop.

The Army used cadmium sulfide because it floresces under ultraviolet light. Filters from monitoring stations nationwide were sent to Dugway, where they were examined by microscope to see how many particles they contained. That showed how far chemicals traveled.

But scientific studies showed since the early 1930s that cadmium and its compounds are dangerous, that they cause cancer and disease of the lungs, kidney and liver. The Army said it didn't realize that danger until the early '70s. Meanwhile, similar tests had continued, some over Utah.

Scientists say the Army should have known the danger of what it was doing long berfore the tests ever began.

The parts of the documents not released include exaclty how much cadmium sulfide the Army dropped in those tests.

The Army also will not say from what altitude the chemicals were dropped and how fast the airplanes were going.

The Army also will not say how much cadmium sulfide was found at monitoring stations in the 40 states East of the Rockies in the test area.

Without that, the exact danger that the public faced cannot be determined - although the Army says it was small. The Army says release of the information would endanger national security.

The Deseret News has appealed that decision by Army lawyers to the secretary of the Army. If he denies it, the newspaper has the option of suing in federal court to try to obtain the final pieces of the puzzle.

The Deseret News is not the only one wanting to know exactly how dangerous the tests were. Rep. Wayne Owens, D-Utah, is working on a letter seeking release of similar information - and is planning to ask several of his high-powered colleagues to sign it because of testing in their areas.

It does not seem to be an unreasonable request. If the Army can drop chemicals - which scientists say the Army should have known is toxic - over Americans without warning them, the least it can do 34 years later is tell them how dangerous it was.