Authorities recovered the remains of a 10th worker Friday from the Nippon Dynawave Packaging Co. paper mill in Longview, Washington, where a catastrophic chemical tank rupture killed 11 workers on May 26, according to officials. Two workers remain unaccounted for as search crews continue working at the industrial site along the Columbia River, four days after a storage tank containing more than 500,000 gallons of white liquor — a mixture of sodium hydroxide and sodium sulfide used to break down wood for papermaking — collapsed Tuesday morning.

The force of the rupture expelled a flood of the caustic chemical through the facility, blowing out building walls and overturning pickup trucks in its path. White liquor causes severe burns on contact with skin and can produce lung damage if its vapors are inhaled, according to occupational safety guidelines.

Victims named as recovery effort continues

The Cowlitz County coroner’s office has been working to identify remains recovered from the site. Among the 11 confirmed dead are Tyler Covington, a mill employee described by family members as the trivia champion of the family, and his brother Brad Covington, who also worked at the plant. A third brother, Kole Musgrove, died in the collapse as well, according to the family. Musgrove, a grandfather, was known in his community for helping neighboring farmers cut hay during harvest season.

Gilbert Bernal, an electrician at the mill, was also among those killed. His wife, Courtney Serad, told the Associated Press that Bernal “loved his job and loved working with his hands.” John Forsberg, a volunteer with Cowlitz County Search and Rescue, was confirmed dead alongside Bernal, who was also a search-and-rescue volunteer, according to the county sheriff’s office.

Two additional victims were identified as Matt Amos and Rex Czuba, co-workers whom colleagues described as experienced mill hands. Kaitlyn Kincaid, whose husband survived the collapse, told the AP that her husband “watched people he cared about die right in front of him.”

Investigation underway

The Washington State Department of Labor and Industries has opened an investigation into the cause of the tank failure. Nippon Dynawave, a subsidiary of the Japanese conglomerate Nippon Paper Industries, has not issued a public statement on the cause of the collapse as of Friday.

The disaster is the deadliest industrial accident in Washington state since the 1998 explosion at the Equilon oil refinery in Anacortes, which killed six workers. It follows a series of chemical-tank incidents across the country in recent months, including a cracked methyl methacrylate tank in Garden Grove, California, that prompted evacuation orders for 40,000 residents in late May, and a chemical leak at a West Virginia silver recovery plant in April that killed two workers and sent approximately 30 others to hospitals.