HERMISTON -- The Umatilla Chemical Depot resumed incineration Monday morning, destroying four rockets after a five-day hiatus triggered by workers entering an area potentially contaminated by nerve agents, officials say.

"It went fairly smoothly," said Rick Kelley, spokesman for incinerator contractor Washington Group International.

The decision on how many M55 rockets with sarin nerve agent will be destroyed today will come after senior managers examined Monday's performance, said Mary Binder, depot spokeswoman.

On Saturday, workers started going into the plant 35 miles south of the Tri-Cities to clean up and remove some waste, but only in the highest-level protective suits, Kelley said.

He said safety precautions at the facility have gotten stricter after they've studied how two workers wearing gas masks and rubber hooded suits accidentally entered the wrong room Sept. 14. The workers were not exposed to chemical agents.

Now, even workers dressed in lower levels of protective suits must follow rules, such as staying on camera at all times, as if they are in the most dangerous areas, Kelley said.

Managers have been re-emphasizing in briefings that workers must be aware of their surroundings and consider the consequences of their actions.

In another development, Circuit Court Judge Walter Edmonds in Multnomah County denied a motion Friday for an injunction to prevent the incineration of chemical agents.

Portland-based attorney Stu Sugarman, who filed the claim on behalf of Hermiston anti-incineration group GASP, said he was "surprised and disappointed."

He said GASP members are discussing whether to appeal.