Blast rocks gas plant along Columbia River

A large explosion rocked a natural gas processing plant on the Washington-Oregon border Monday, injuring four workers, causing about 400 people to evacuate from nearby farms and homes, and emitting a mushroom cloud of black smoke that was visible for more than a mile.

The 8:20 a.m. blast at the Williams Northwest Pipeline facility near the Washington town of Plymouth, along the Columbia River, sparked a fire and punctured one of the facility’s two giant storage tanks for liquefied natural gas.

Benton County Sheriff Steven Keane said a relatively small amount of gas leaked from the tank to the ground in a moat-like containment area. But it then evaporated.

“I think if one of those huge tanks had exploded, it might have been a different story,” Keane said.

The fire at the facility about 4 miles west of Plymouth was extinguished within a couple of hours.

One of the four injured workers was transported to a Portland hospital specializing in burns, he said. The other three were taken to a hospital in Hermiston, Ore., where spokesman Mark Ettesvold said they were treated for injuries that did not appear to be life-threatening.