A chemical tank that exploded at a Washington state paper mill earlier this year and left nearly a dozen people dead was known to be unfit for service almost a year prior to the deadly blast, a federal investigation report released on Aug. 28 found.
The explosion that injured several others, including one firefighter, took place May 26 at the Nippon Dynawave Packaging Company in Longview, Washington.
The U.S. Chemical Safety and Hazard Investigation Board, in an update released on its investigation into the catastrophic failure of a 1.2-million-gallon atmospheric storage tank at the mill, found the company was told 10 months earlier the tank was "not fit for continued service and could fail."
When it ruptured, the tank released some 900,000 gallons
of "extremely hot highly caustic white liquor," killing 11 employees and seriously injuring three others. Five other employees also suffered minor injuries, according to the report.
The blast sent several mill workers and one firefighter to local hospitals for treatment after suffering injuries including chemical burns. Scott Goldstein, chief of Cowlitz 2 Fire & Rescue, said injuries ranged from "critical, severe to minor," USA TODAY previously reported.
A 'high likelihood/consequence of failure'
"The investigation found an inspection of the exterior shell of G Tank conducted in July 2025 − approximately 10 months before the fatal incident − identified that significant portions of the tank’s carbon-steel shell had thinned below the calculated minimum safe thickness," investigators wrote in the report.
Unless it was repaired, the investigation found, there was a “high likelihood/consequence of failure."
USA TODAY has reached out to Nippon Dynawave Packaging Company for comment.
Despite the inspection’s findings, the report continues, the tank remained in service until catastrophic explosion.
The report is part of an ongoing investigation, the federal agency said, adding it was still working to determine the official cause of the explosion.
Natalie Neysa Alund is a senior reporter for USA TODAY. Reach her at nalund@usatoday.com and follow her on X @nataliealund.
This article originally appeared on USA TODAY: Chemical tank was deemed unsafe months before deadly Washington blast
