US News
Chemical tank in Washington state was deemed unfit for service 10 months before fatal collapse, federal board says
A federal investigation found that paper mill operator Nippon Dynawave Packaging failed to perform recommended repairs or take a thinning chemical tank out of service before a May failure killed 11 people.
The short version
- A chemical tank at a Longview, Washington paper mill failed in May 2026, releasing 900,000 gallons of caustic liquid, killing 11 workers, and injuring several others.
- Federal investigators found an inspection contractor had labeled the tank unfit for service 10 months prior due to severe wall thinning, but the mill operator did not complete recommended repairs or remove it from service.
- The U.S. Chemical Safety Board's investigation into the precise root cause of the structural failure remains ongoing.
Key facts
- An inspection contractor, Applied Technical Services LLC, determined in July 2025 that a chemical tank at the Nippon Dynawave Packaging mill in Longview, Washington was unfit for continued service due to wall thinning below safe thresholds.[Associated Press]
- The contractor issued further warnings after follow-up inspections in October 2025 and February 2026, recommending internal inspections and shell repairs.[Associated Press]
- The U.S. Chemical Safety Board reported that Nippon Dynawave did not carry out internal inspections, perform shell repairs, or take the tank out of operation before its failure on May 26, 2026.[Associated Press]
- The failure released approximately 900,000 gallons of caustic white liquor, destroying building walls and flooding lower level work areas where morning meetings were taking place.[Associated Press]
- Eleven workers were killed in the incident and several others, including a responder who entered chemical pools without being warned of the spill's nature, suffered serious chemical burns.[Associated Press]
- The Washington Department of Ecology cited Nippon Dynawave with 35 environmental violations in the week preceding the federal report release.[Associated Press]
What remains uncertain
- The U.S. Chemical Safety Board stated that its investigation into the precise cause of the tank's failure remains ongoing, with complete findings to be published in a final report.[Associated Press]