The Tacoma blast | "It's amazing there were not more" hurt

The scene inside the Atlas Castings & Technology foundry was hellish Sunday: the burned wreckage of a propane tanker truck; the critically injured driver's shoes and jeans; the overwhelming stench of propane as it vented into the atmosphere.

Yet the scene also inspired wonder that more people weren't killed or even hurt.

At the spot where the truck exploded, the radiator and wheels — but little else — remained. Truck pieces were strewn over hundreds of yards. Fifty feet from the site of the explosion lay the truck's tanker section, tangled in power lines it had brought down.

The truck, delivering propane, exploded Saturday at the foundry, rocketing a fireball into the air. Four were injured in the blast, with driver Charles McDonald, 64, still in the intensive-care unit at Harborview Medical Center on Sunday night. Three others with minor injuries were released Saturday from a Tacoma hospital.

Although the precise cause won't be known for some time, something went wrong when the highly flammable liquified gas from the truck's cargo tank was being transferred to two storage tanks at the foundry. Propane is a backup fuel source at the foundry.

"There was a leak, and the propane found an ignition source," Tacoma Fire assistant chief Dan Crotty said.

Fire officials haven't determined what ignited the propane, but it may have been welding or an open furnace, Crotty said. Atlas Chief Executive Duane Britschgi said he was unaware of welding taking place nearby.

Rare accident

McDonald arrived at Atlas with about 8,000 gallons of propane in his truck. He had been trained in the process of transferring propane from truck to tank, said Bob Cox, chief executive of Molalla, Ore.-based IXL Transportation Services, for whom McDonald drives.

Experts say accidents like the one in Tacoma are rare and that the transfer process is highly regulated.

Gene Wendt of Northwest Consulting — a Vancouver, Wash., firm that trains propane tanker drivers — said the gas typically is transferred between a truck and storage tanks using two hoses — one to pump liquid gas into the storage tank and the other to let vapor escape from the storage tank and flow back into the truck tank. The hoses, which are hooked up by the truck driver, can withstand 1,700 pounds of pressure before bursting, Wendt said.

"There are a bunch of scenarios on what possibly could fail," Wendt said, including hose couplings, tank fittings or the hoses themselves. Any number of things could ignite leaked propane, he said, including several that have nothing to do with the propane transfer itself.

Hundreds of propane transfers occur safely in the U.S. every day, Wendt said. The U.S. Department of Transportation requires tanker-truck drivers to undergo training every three years.

McDonald's truck had two systems — one manual and one automatic — for shutting down the flow of gas in an emergency, Cox said.

Cox and Britschgi say a smaller explosion and fire preceded Saturday's big blast. The lull likely gave those inside the foundry the chance to flee.

"It's amazing there were not more injuries," Cox said.

Charred pair of shoes

On Sunday, reporters were allowed to briefly view the aftermath. Near the truck wreckage lay a pair of shoes and a pair of jeans, which workers at the foundry identified as the driver's. One of the shoes was badly charred. The jeans were blackened with soot and dirt.

Workers said McDonald was thrown a great distance by the blast and then managed to crawl farther from the inferno.

About 32 workers were at the plant Saturday, Britschgi said. On weekdays, about 300 work there. Until three weeks ago, hundreds were working weekends. Managers ran the plant at full capacity to meet production demands, workers said.

The reporters' visit was cut short because of safety concerns. A white vapor was escaping from the foundry's propane tank pipes. Fire officials said the plan was to let the residual gas escape until the tanks were empty, then bring in propane experts to secure them. The foundry's propane tanks did not explode but were destroyed, Crotty said.

Force moved walls

Saturday afternoon's explosion shut down nearby highways and kept firefighters working past sunrise.

The blast catapulted one of the truck's axles onto the nearby Highway 16 overpass.

Some businesses near the foundry remain closed Sunday because of an evacuation order, and the foundry still did not have power.

The force of the explosion moved walls and support beams inside some foundry buildings, making them unsafe to enter, Crotty said.

Early Sunday, the Washington State Patrol reopened Highway 16 near the foundry.

Britschgi said he knew of two employees with minor injuries. One suffered facial burns; the other aggravated a bad knee. St. Joseph Hospital in Tacoma treated another person for leg and knee injuries.

The foundry is on 18 acres in the Nalley Valley industrial area near the intersection of Interstate 5 and Highway 16. Atlas manufactures iron castings and recently built parts for the new Tacoma Narrows Bridge.

In 2002, a fire at the foundry, started by a welding remnant left smoldering, caused about $850,000 damage.

The state Department of Labor and Industries will investigate Saturday's accident.

Cox said the accident is a first for IXL. McDonald has been driving for the company for a couple of years.

"We are concerned about him," Cox said. "And all our thoughts and prayers are with his family."

Lauren Vane: 253-234-8604 or lvane@seattletimes.com