Washington Mill Kept Faulty Tank Running for 11 Months Before Fatal Blast
Published on 09/04/2026 at 11:27 | Editorial boerse-global.de
A US safety board has found that an industrial storage tank at a Washington state mill remained in service for nearly a year after being declared unfit, before its collapse killed 11 workers and seriously injured three more.
The findings carry a stark warning for UK employers operating pressure vessels and storage tanks: deferring repairs on equipment flagged as unsafe can turn a maintenance backlog into a fatal incident.
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Tank Declared Unfit But Kept in Use
The Chemical Safety and Hazard Investigation Board (CSB) determined that the "G Tank" at the Nippon Dynawave mill in Longview, Washington, was first identified as unfit for continued service in July 2025.
Despite that designation, the vessel stayed in active operation. Follow-up inspections in October 2025 and February 2026 confirmed the tank walls were under-thickness, yet the facility neither carried out repairs nor reduced the tank's operating capacity.
When the structure finally gave way on May 26, 2026, it released roughly 900,000 gallons of caustic white liquor being stored at around 200 degrees Fahrenheit. The specific technical cause of the breach remains under investigation.
Regulatory Pressure Building on Storage Vessels
The CSB's findings come as the agency pushes for tighter oversight of industrial equipment. Chair Steve Owens recently recognised Didion Milling in Wisconsin for completing nine safety recommendations stemming from a fatal 2017 dust explosion. The company has cooperated since August 2025 to implement engineered safeguards and a formal combustible dust programme.
New environmental and safety rules for storage vessels are also being phased in across North America. In Canada, the first milestone for volatile organic compound (VOC) regulations took effect on March 7, 2026, targeting high-benzene storage tanks.
A further tightening follows on December 31, 2026, when vapour leak thresholds for around 434 facilities drop from 10,000 to 1,000 parts per million.
Inspection Failures Extend Beyond US Borders
The Washington case echoes a broader pattern of oversight gaps. An investigation into a shipyard accident that killed 10 workers on August 14, 2026, in Sitakunda, Bangladesh, found inspectors had issued safety certificates for a ballast tank without conducting a physical inspection. The probe cited at least six safety lapses and attributed the deaths to yard owner negligence.
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Historical maintenance habits are also under scrutiny. A report into a nitrogen regulator failure at a copper concentrator in January 2025 found workers had used an informal and unsafe method for freeing stuck valves for more than two years. The practice led to an overpressure event exceeding 3,200 kPa, causing a projectile injury to a staff member.
Legal proceedings are ongoing elsewhere. A bus depot operator in Alberta faces a court appearance on September 28, 2026, on 10 Occupational Health and Safety charges linked to a January 2025 propane explosion that injured five workers. Allegations include failing to follow manufacturer manuals and not providing flame-resistant outerwear.
