Washington Mill Tank Failure Followed Months of Warnings, Investigators Find
Published on 08/28/2026 at 21:17 | Editorial boerse-global.de
Federal investigators have determined that a chemical storage tank at a Washington state paper mill was flagged as unfit for service 10 months before it catastrophically failed, killing 11 workers. The finding raises serious questions for industrial employers about the consequences of delaying critical maintenance, with the U.S. Chemical Safety and Hazard Investigation Board (CSB) confirming that structural degradation was identified well in advance.
Tank Declared Unfit for Continued Use
The 1.2-million-gallon atmospheric storage vessel was located at the Nippon Dynawave Packaging pulp and paper mill in Longview, Washington. Inspections carried out in July 2025 by contractor Applied Technical Services LLC found significant structural thinning in the tank, according to the CSB report released on Friday.
The contractor advised that the tank was not suitable for continued operation and recommended internal inspections alongside necessary repairs. Investigators found, however, that these actions were not completed before the equipment failed.
Fatal Failure on the Morning Shift
On May 26, 2026, the tank suffered a total collapse, releasing roughly 900,000 gallons of white liquor — a caustic chemical essential to the papermaking process. The sudden discharge fatally injured 11 employees and left three others with serious injuries.
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Chronological data from investigators shows a process upset occurred at 1:55 a.m. on the day of the incident. Although flow to the tank was stopped by 4:08 a.m., the vessel stood at approximately 90% capacity by 6:22 a.m. The structural failure came less than an hour later, at 7:09 a.m.
Environmental Fallout and Potential Fines
Beyond the federal safety probe, the Washington Department of Ecology issued a notice on Thursday identifying 35 environmental violations linked to the incident. State regulators found that the chemical spill reached storm drains, the local sanitary system, and the Columbia River.
The department has indicated the company could face fines of up to $10,000 per violation for each day the conditions persisted. Nippon Dynawave Packaging now has a 30-day window to provide a formal response to the state's findings.
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The CSB continues its examination of the failure to determine the final cause and to develop potential safety recommendations for the wider industry.
