The tank, which could hold about 900,000 gallons (3.4 million liters), was more than half full when it ruptured Tuesday morning during a shift change at the plant along the Columbia River in Longview, a city of about 40,000 people with long ties to the Pacific Northwest’s paper and lumber industries. The chemical, white liquor, is a highly alkaline mixture made primarily of sodium hydroxide and sodium sulfide that is used along with heat to break down wood fiber into pulp for kraft paper production.
Authorities initially delayed the search for the nine missing workers because of concerns the damaged tank might collapse further. By Wednesday, crews determined the tank contained less liquid than originally believed and that the structure was stable enough to allow the search to resume. Scott Goldstein, a Cowlitz County fire chief, said the operation would be slow and methodical because the precise location of the missing personnel remains unknown.
“We do not know where all nine are,” Goldstein said.
The likely death toll rose to 11 after an injured person died Wednesday, authorities said. A firefighter who responded to the scene was among the eight injured but was treated and released from a hospital.
Authorities have not released the names of the dead or missing, but some have been identified by friends and family. Todd Cornwell said his friend, Gilbert Bernal, an electrician at the plant, was the first confirmed death. Bernal and Cornwell knew each other through church and were in the same Bible study group.
“He was always there willing to help in whatever needed to be done,” Cornwell said. “When the local church school started flooding, he was one of the people there.”
The Nippon Dynawave packaging plant employs about 1,000 people and produces materials for tissues, printing paper, cups, plates and cartons. It sits along the Columbia River adjacent to other timber, paper and chemical businesses.
Brian Williquette, a chemical supplier who was at the plant Tuesday morning, said he heard an alarm over the intercom and initially wondered if it was a drill. He was able to evacuate without seeing the damage.
“It’s just unfathomable,” he said at a community vigil Tuesday. “There’s not anybody that lives here that doesn’t know somebody at a paper mill.”
Crystal Moldenhauer, a Longview resident, said friends at the plant remain unaccounted for. “We’re all still waiting for answers,” she said. “There’s families that have been torn apart, and we don’t know why.”
State officials said the rupture has not affected the safety of air or drinking water in Longview. Some of the white liquor entered a drainage ditch and flowed into the Columbia River, one of North America’s largest waterways. The U.S. Environmental Protection Agency said it had observed no effects on the river, though it urged residents to stay away from ditches and dikes as a precaution.
The incident was the second chemical-tank emergency on the West Coast in days. On Monday, thousands of Southern California residents were evacuated after an overheated tank at an aerospace plant in Gardena threatened to release anhydrous ammonia. Those evacuation orders were lifted Tuesday night.
Chemical engineering professor Stephen Kmiotek of Worcester Polytechnic Institute said chemical tanks like the one that failed are used widely across industry and are generally safe when properly maintained and inspected. “But it’s important that companies keep up proper maintenance and inspections, particularly after the tanks get older,” he said.
Nippon Paper Group said in a statement Wednesday that it was offering its “deepest condolences and heartfelt sympathies to the bereaved families.”
The U.S. Chemical Safety and Hazard Investigation Board announced Wednesday that it had launched an investigation into the rupture. Board Chairperson Steve Owens said the goal was to “determine how it happened and what can be done to prevent something like this from happening again.”