Key facts
- A chemical tank at Nippon Dynawave Packaging Company in Washington failed on May 26, killing 11 workers.
- An inspection contractor found the tank "not fit for continued service" 10 months prior to the failure.
- The contractor identified "significant thinning" below the minimum safe thickness in the tank's lower regions.
- Nippon Dynawave did not perform recommended internal inspections or repairs between the July 2025 inspection and the failure.
- The tank released approximately 900,000 gallons of caustic white liquor.
- The U.S. Chemical Safety Board is investigating the incident.
A chemical tank at a Washington state paper mill was deemed "not fit for continued service" 10 months before it catastrophically failed in May, killing 11 workers, according to an update from the U.S. Chemical Safety Board. The federal agency's ongoing investigation into the May 26 incident at Nippon Dynawave Packaging Company revealed that an inspection contractor had identified "significant thinning" below the minimum safe thickness in the tank's lower regions during a July 2025 inspection.
The contractor recommended internal inspections and shell repairs, noting the tank was "Priority 1: Not fit for continued service unless corrected." However, the company reportedly performed no internal inspections or repairs between that assessment and the failure. The tank released approximately 900,000 gallons of caustic white liquor, a substance used in paper production capable of causing severe burns, which flooded building areas where employees were starting their morning shifts.
In addition to the fatalities, several other workers and a firefighter were injured. The U.S. Chemical Safety Board's Chairperson Steve Owens expressed concern that the tank was not promptly removed from operation or repaired after the inspection findings. The company has not yet commented on the findings, and a message was left seeking comment from the inspection contractor, Applied Technical Services LLC.