WASHINGTON — It may have sounded awful when the Pentagon reported last year that nearly 6,000 soldiers may have been unwittingly exposed to germ and chemical weapons in 50 tests conducted worldwide from 1962 and 1974 by Army scientists based in Utah.

But congressional investigators said Friday that figure was just the tip of the iceberg.

The U.S. General Accounting Office, a research arm of Congress, said those Pentagon-reported numbers were just for one series of experiments, called Project 112 or Project SHAD. "We have determined that hundreds of such classified tests and research projects were conducted outside Project 112," GAO officials said in a new report released Friday.

In fact, the GAO said it quickly found that at least 100 secret germ and chemical experiments were conducted at Utah's Dugway Proving Ground alone, or more than double the number of tests conducted under Project 112 during the same time period. The report said hundreds more secret tests were conducted in the 48 contiguous states.

So the GAO said the Pentagon, which declared last June that its work in identifying potential chemical and germ arms victims for Project 112 was complete, should continue probing further now to try to identify soldiers and civilians possibly exposed in all those other tests. In response, the Pentagon said it is planning to try to do so.

The Deseret Morning News has shown through the years, through documents obtained through the Freedom of Information Act, that thousands of open-air trials occurred in Utah with chemical, biological and radiological weapons, often upwind from populated areas.

The newspaper also first reported the Project SHAD and Project 112 tests, many of which were conducted at sea. Some sailors had sought the newspaper's help, complaining they were suffering from cancer and nervous system ills they blamed on the tests. But Veterans Affairs denied claims because the Army said the tests never occurred.

Despite the newspaper obtaining reports and plans of some of those tests, the Pentagon continued for years to deny they occurred.

But after pressure from national media, members of Congress, the VA and sailors, the Pentagon finally said in May 2002 that some initial research showed such tests happened. It said last June that it had identified all the places and the names of veterans likely involved.

The new GAO study was ordered to measure the adequacy of that recent Pentagon work. The GAO said the Pentagon generally did a good job of identifying all Project 112 tests and most of the veterans involved. But it said a few veterans and many civilian workers were likely missed because records of some tests have yet to be found.