HERMISTON, Ore. -- The Oregon Department of Environmental Quality has begun reviewing materials provided by the Umatilla Chemical Depot that explain the reason for three recent fires at the rocket incineration site.

Meantime, the U.S. Army has formed a task force to look into the small fires that occurred at Umatilla and at another chemical-weapons destruction site in Arkansas -- but the Army said a preliminary assessment concluded that safety at the incineration operations won't be reduced even if such fires continue.

Continuing to destroy the M-55 rockets containing the nerve agent GB is the safest way to deal with them, according to a news release Thursday from the Army's Chemical Materials Agency at Aberdeen Proving Ground in Maryland.

DEQ, Umatilla officials discuss safety

Dennis Murphey, the administrator of the chemical demilitarization program for the Oreogn DEQ, said all the Umatilla fires happened as the rockets were being cut in a containment room. Though the sarin, a deadly nerve agent, had already been drained from the rockets, the fires were enough of a concern that the agency halted the destruction of the chemical weapons at the Umatilla Depot.

On Thursday, Umatilla officials met with the DEQ to discuss plans for making the depot safer, Murphey said. The DEQ had requested documents on what caused the fires, and what the depot can do to reduce their frequency.

Murphey said the DEQ expects to have an answer within the next few days about when the depot will be allowed to resume destroying the weapons.

The Umatilla Depot had about 12 percent of the national stockpile of chemical weapons when the incineration project started in September.

Army's preliminary finding is safety OK

Similar fires to those at Umatilla have occurred in nearly identical incinerators at the Pine Bluff Arsenal in Arkansas. At Umatilla, fires occurred on April 7, April 23 and May 18; the Pine Bluff Arsenal incinerator had fires on May 11 and May 22. Other incinerators have had fires, but not at such a great frequency.

That said, the Army on Thursday seemed less concerned than Oregon officials.

"Even with the increase in the frequency of rocket fires, the public is at reduced risk with continued M-55 GB-filled rocket disposal destruction process rather than delayed disposal and extended storage," the Army release said.

The Army task force being formed includes experts from the Army's CMA; Washington Group International, a company running the incineration process at both sites; the Army Corps of Engineers; Southwest Research Institute; Sandia National Laboratory; EG&G; and the Army's Armament Engineering and Technology Center.

The Army said the fires were all contained safely inside explosive containment rooms, and "there was never any danger to personnel or any release of agent to the environment." And the release said that should continue to be the case even if there are more fires, based on a preliminary assessment by the Army Engineers of the explosive containment rooms' functions and integrity, the Army said.

"The ECR structural integrity, including explosion containment capability, is not compromised" by repeated small fires such as those that have occurred, the Army's statement said.

The assessment concluded that "the fires have an insignificant impact," according to the release.