HERMISTON -- A date may be set soon for destruction of chemical weapons rockets to resume at the Umatilla Chemical Depot, officials indicated Thursday after meeting in Portland.

As the depot began its third week of a stand-down Thursday, representatives from the state, the Army and the incineration contractor met in Portland to discuss investigations into three recent rocket fires at the plant.

The fires are one of two issues recently raised about depot operations. The U.S. Centers for Disease Control and Prevention issued a letter last month pushing for more reviews and improvements in response to an internal safety audit at the incineration facility. The audit by Washington Group International reviewed a number of worker errors that slowed operations.

The Portland meeting was a chance to discuss what had been done to lessen the damage of any future fires, said Dennis Murphey, administrator for the Oregon Department of Environmental Quality's chemical demilitarization program.

DEQ ordered the facility near Hermiston to stop destroying M55 rockets filled with GB sarin nerve agent May 18 after the third rocket fire ignited as a blade was cutting through its motor section.

Although no cause has been found, the investigation determined the reinforced concrete room where each of the fires happened can withstand such fires.

An Army Corps of Engineers study concluded the room's "structural integrity, including explosion containment capability, is not compromised," the Army Chemical Materials Agency said Thursday.

The facility also has made several modifications designed to lessen the damage from future fires, said Doug Hamrick, project general manager for Washington Group International, the operator of the incineration facility.

Among the modifications are increased fire suppression sprays on the machine that cuts the rockets into pieces, he said.

Don Barclay, depot site project manager, said he hoped there might be a decision when to restart as early as today.

Murphey said his office wouldn't wait for test results from nine rocket propellant samples sent to New Jersey for examination. The investigation is starting to focus on the propellant as a possible cause of the fires.

The problem and investigation are much broader than just the Oregon plant, he said. Rockets also have caught fire during processing at incinerators at Pine Bluff, Ark., and Anniston, Ala.

There also is concern that problems with the rocket propellants could affect a planned neutralization facility in Blue Grass, Ky., Murphey said. The plant's original design called for using a rocket-cutting process similar to the Umatilla depot's.

Although the most recent shutdowns have been caused by the rocket fires, prior shutdowns were blamed on worker errors.

One mishap shut the facility down for almost a month in December after two workers unclamped an incorrect door, allowing sarin vapors to escape.

That prompted Washington Group International to conduct the internal audit, which was finished at the end of March. It highlighted such problems as a "poorly defined leadership structure," backlogged work orders and a system with no clear method to prioritize more routine projects.

The report's recommendations were being implemented even before it was completed. The report confirmed what Barclay said he thought he'd observed in the first four months after the facility started destroying rockets in September.

Barclay said he has seen significant improvements, and Hamrick agreed the response to the fires in April and May reflected some of the improvements.