PORTLAND -- An Army expert witness claimed Raytheon cleaned up the incinerator site where more than four dozen workers were injured before the Occupational Safety and Health Administration investigated the accident.

"It's my understanding OSHA officials said they had never seen such a clean site," said Dr. Leslie Hutchinson, an occupational and environmental medicine specialist.

Hutchinson was called in by the Army to help investigate the Sept. 15, 1999, accident that injured more than four dozen construction workers at the Umatilla Chemical Depot.

Monday, he testified in U.S. District Court in Portland that welding fumes and poor ventilation in the incinerator building at the Umatilla Chemical Depot caused the workers' injuries.

The workers are suing the Army, claiming they were exposed to the chemical agents stored at the depot, about 35 miles south of Kennewick.

The workers were building the incinerator plant that will be used to destroy the 3,717 tons of the nerve agents sarin and VX and the blister agent mustard when they simultaneously became ill.

"None of (the workers) showed any signs of chemical exposure," Hutchinson said during the ninth day of the trial.

Hutchinson's testimony, which took most of the day, centered around his belief the workers were affected by welding fumes at the site.

Hutchinson was part of an Army team that investigated the accident in the weeks following the mysterious event. He interviewed 83 workers that had complained of symptoms the week of Sept. 15, 1999, and wrote a six-page report outlining his theories of what happened that day.

"Because the symptom picture focused the list of possible causes to a few toxicants that could come from welding fumes or be generated by burning materials in the plant during welding activities, the welding activities and ventilation are likely common elements in the incidents that have occurred to date," Hutchinson wrote.

But the OSHA report of the incident ruled out welding fumes as a possible cause.

The report said welding activity had slowed in the building. In July 1999, there were 40 welders helping build the incinerator plant. But by September, there were only 18 on staff.

And only four welders were injured in the incident, pointed out James McCandlish, the Portland-based attorney representing the workers.

"And none of them were welding at the time," McCandlish said.

Hutchinson said workers had told him welding was going on at the time of the incident, and he had never seen the OSHA report.

McCandlish also questioned Hutchinson's lack of comment about the Army's medical response in his lengthy report, especially since Hutchinson was the only doctor on the Army's investigative team.

"Isn't it true you were told not to focus on medical response in your report?" McCandlish asked Hutchinson.

Hutchinson said he was only told to focus on the workers' injuries and what might have caused them. But McCandlish produced an e-mail from Dr. Jose Ortiz, who was in charge of the depot's medical clinic at the time of the accident, that refuted Hutchinson's answer.

The e-mail, which outlined Ortiz's comments about the investigation, stated: "Finally, I am impressed (but not surprised) about the lack of comment on the medical response. I had mentioned this to Dr. Hutchinson but he noted that he was instructed not to focus on this part of the event."

When confronted with the e-mail, Hutchinson said he had expressed his concerns about the note to Ortiz.

"He said he was just trying to cover himself," Hutchinson said.

The trial ends today with closing arguments, but it likely will be months before Judge Dennis J. Hubel makes a decision in the case.