Ronald Lamoreaux defended the way he handled the report of possible poisoning by sarin gas four years ago, saying there was no sign of any poison gas leak when emergency crews responded, and follow-up testing failed to show any leak.

"Based on the information I had from reliable sources ... I did use my judgment," Lamoreaux said.

His testimony came during the fourth day of a non-jury trial in U.S. District Court that pits the Army against workers who claim they were poisoned by sarin leaking from one of the bunkers where chemical weapons are stored.

The workers were building an incinerator -- which was recently completed -- that will be used by the Army to burn nearly 4,000 tons of chemical weapons -- about 12 percent of the nation's stockpile.

Lamoreaux was in charge of the Umatilla Chemical Depot while the military commander was away on business Sept. 15, 1999.

Workers at the construction site, including 34 sent to the hospital, described symptoms from troubled breathing to intense chest pain and vomiting.

James McCandlish, the lawyer representing the workers, asked Lamoreaux if he had heard any reports of dead animals near the depot at various times during the 1980s and '90s without investigating.

Lamoreaux, who retired in 2001, replied "absolutely not."

"You can rest assured that if any reports of dead animals had been made, it would have been thoroughly investigated," he said.

McCandlish introduced a statement from a ranch hand who claimed he found more than a dozen dead cattle, once in the mid-70s and again in 1989, at the same spot near the northeast corner of the depot.

The statement indicated the deaths were unusual, with the livestock carcasses clustered together and showing signs of bleeding from the eyes, nose and mouth.

Lamoreaux insisted no reports of the cattle deaths were brought to his attention, suggesting they died of natural causes.

McCandlish also questioned Lamoreaux about his knowledge of emergency procedures, studies on rapid shifts in wind direction and handling of leaky weapons.

Lamoreaux replied, "I'm not a chemist. I'm not an engineer, and I'm not a meteorologist, and I never claimed to be one."

McCandlish told U.S. District Judge Dennis Hubel the response indicated "the person who made the call at the scene has very little knowledge of chemical weapons."

But in a sharp exchange with McCandlish, Lamoreaux immediately replied: "I would refute that. I feel that I have a vast amount of knowledge."

In opening arguments Monday, McCandlish claimed the Army was negligent in its response to a "major medical emergency" because it did not test for chemical agent until three hours after the workers got sick and did not send a doctor to the scene.

The Army argued it was not responsible for medical care because paramedics and a company manager at the scene determined the symptoms were caused by industrial fumes and not by chemical agents stored nearby.