Image Some of the barrels recovered from the warehouse. The stencil reads: "al-Karama General Company Fuel TG-02K1 2001." Credit... Dennis Marcello

Several soldiers said one young officer acting on his own — Lieutenant Clonch, now a major — created an unclassified record that eventually allowed the veterans to confront the Army.

The record, a memo summarizing what happened at the warehouse, did not declare what the soldiers had inhaled; Major Clonch said in an interview that he was never able to find out. But he made a point of sharing his memo, which noted the positive field test results for nerve agent, with the rank and file.

“The account I did was for everybody’s medical record,” he said. “That was really the only record we were given.”

The record did not spur the Army to disclose what it knew, or to examine the victims for long-term health problems. Several victims said it did not even make its way into their records. But they retained personal copies, which ultimately provided a means for one of the exposed veterans, Mr. Marcello, to try years later to have the episode recognized.

Mr. Marcello said he used photographs from the warehouse and the lieutenant’s memo as part of the public-records request he first filed in 2009, seeking to force the Army to reveal the details.

Mr. Carson, after reviewing Mr. Marcello’s long-idle records requests at the request of The Times, approved the release of the two-page report last week. Mr. Marcello received a copy of the record Tuesday afternoon.