A large explosion hit a natural gas processing plant on the Washington-Oregon border Monday, injuring five workers, causing about 400 people to evacuate from nearby farms and homes, officials said.
The 8:20 a.m. blast at the Williams Northwest Pipeline facility near the Washington town of Plymouth, WA, 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, blowing away to the northeast, he said.
“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 out within a couple of hours.
One of the injured workers went to a Portland, OR, hospital specializing in burns, he said.
Benton Fire District 1 Capt. Jeff Ripley said another four people went to local medical facilities. None of the injuries were life-threatening, he said.
Deputies went door to door to homes and farms within a 2-mile radius, evacuating about 400 residents as a precaution.
By Monday night, the evacuation zone reduced down to a 1-mile radius, the Benton County Emergency Management agency said. Road and river restrictions ended up lifted.
About 75 people checked into a shelter set up in Oregon at the Umatilla County Fairgrounds, but emergency officials said they expected few to stay the night.
The facility provides supplemental gas during times of high demand for a 4,000-mile pipeline stretching from the Canadian border to southern Utah. Its two storage tanks for liquefied natural gas each have a capacity of 1.2 billion cubic feet, Williams spokeswoman Michele Swaner said. The one that punctured was about a third full.
Swaner said the 14 employees working at the time were all safe. At least 18 people work at the facility.
She added it was too early to determine the extent of the damage or the cause of the explosion. The pipeline shut down in the area of the storage facility, but was still carrying gas on other stretches.
Video taken by a Washington State Patrol bomb squad robot was under review.
Emergency crews and Williams personnel entered the hazard area to assess the situation Monday night, the emergency management agency said in a statement.
A pipeline engineer with the Washington Utilities and Transportation Commission will investigate the cause of the explosion and communicate with the western region of the U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration, the commission said.
Workplace safety investigators from the Washington Department of Labor & Industries will join the investigation, department officials said.
The state Pipeline Safety Program regulates 28 pipeline companies and inspects more than 24,000 miles of natural gas and hazardous-liquid pipelines in Washington.
Williams operates about 15,000 miles of interstate natural gas pipelines, according to its website.
Williams Partners’ subsidiary Northwest Pipeline LLC owns the liquefied natural gas facility.
There was no pipeline rupture, and no customers suffered a lack of service, company officials said.