HERMISTON -- A bumped emergency stop button halted the destruction of the first rocket sent through the Umatilla Chemical Depot's incinerator for about four hours Wednesday morning.

About 9:25 a.m., Cory Grabeel of Hermiston and Paul Cook of Pasco lifted the approximately 7-foot-long fiberglass tube containing the M55 rocket with GB sarin nerve agent from a pallet of 15 other rockets and placed it on a conveyor belt.

The two operation munitions handlers on C crew were the last to touch the 70-pound rocket, which was moved into a room with 30-inch-thick reinforced concrete walls, punched with three holes and drained of most of its 10.8 pounds of nerve agent.

Then, the first portion of the rocket containing the fuse was chopped off, but the sliding gate the piece fell onto did not open like it should have.

Under normal circumstances, the gate would have opened, dropping the rocket piece into the 1,200-degree furnace below. The furnace would eradicate any residual agent, and eventually the metal parts, now free of agent, would drop into a container outside the incineration plant.

At 2 p.m., the rocket was completely destroyed after depot workers jump-started the electrical circuit controlling the door, said Don Barclay, depot site project manager.

Initially, depot representatives thought the problem was either an electrical one or a mechanical error. The problem was identified after two people in sealed white protective suits entered the reinforced room at about 3:30 p.m., said Rick Kelley, spokesman for Washington Group International, the contractor that operates the incinerator.

The glitch didn't do much to dampen the excitement expressed by officials and area residents at the destruction of the first of 90,000 M55 rockets containing sarin nerve agent. The burn has been in the planning process at least 30 years, and the plant 35 miles south of the Tri-Cities has been preparing for this day for the past several years.

Grabeel said he was glad to see the process started. "We can finally do some work," he said.

He said his family didn't know he was going to be one of the people handling the first rocket.

Cook said he didn't have any butterflies before handling that first rocket. It felt like one of the simulated rockets in a practice run, he said.

At an open house at the Outreach Office in downtown Hermiston later in the afternoon, Bill Whetsler, who has lived in Hermiston for 32 years, said he "couldn't be more pleased."

He said he wasn't at all apprehensive about the startup. "If anything happens, I'm certain they'll fix it immediately."

Whetsler saw incineration as the best way to get rid of the chemical agents stored at the depot, pointing out they couldn't be shipped anywhere else.

Bill Myers, who has lived in Hermiston all of his 70 years, felt the startup "should have happened a long time ago."

He was happy to see the process start and said most people he talked to felt the same way. "I don't think there are even 1 percent of the people in Hermiston that don't want it done," he said.

One of those opposed to the incinerator is Karyn Jones of Hermiston, a founding member of GASP, an anti-incineration group that has filed several lawsuits trying to stop the burn process.

Jones said she felt the door problem was significant, adding that the same thing had happened at other incineration sites.

The problem should make area residents concerned, she said. "They are just starting and already they're having the same problems," she said.

GASP plans to file an injunction Friday asking a Multnomah County Circuit Court judge to halt the burn until a case, referred to as GASP I, is heard in court, Jones said. The case asks that the permits for the incineration facility be revoked and the site use an alternative destruction method.

Barclay said the problems Jones was referring to at other incineration sites actually were with a different door leading to the furnace below the one that did not work at Umatilla. The lower door worked fine Wednesday.

Wednesday was the first step in the destruction of the depot's stockpile of 220,604 munitions and containers filled with 7.4 million pounds of deadly nerve and mustard agents.

Mustard agents stored at the depot date back to World War II. All the nerve agents were brought to the depot for storage between 1962 and 1969.

It is expected to take 10 years to destroy the depot's stockpile, which included the most rockets of any of the eight U.S. sites, depot spokeswoman Mary Binder said.

Two more 15 rocket pallets were moved from the storage igloos about a half-mile to the incineration facility in shipping containers Wednesday afternoon, depot commander Lt. Col. David "Doc" Holliday said.

Another rocket should be destroyed on the incinerator's second processing line today, Kelley said. A third rocket today also is possible.

By Saturday, depot officials expect to be up to processing five rockets.

The chemical agent drained from the rockets will be stored in separate vats until enough is collected then burned in one of two liquid incinerators at 2,700 degrees to destroy the agent. Officials expect it will be a month before that occurs.