Federal Investigators Found Chemical Tank Unsafe Months Before Deadly Washington Explosion

Federal investigators disclosed Friday that an inspection contractor had flagged a chemical storage tank at a Washington state paper mill as unsafe for continued operation in July 2025, a full decade before the catastrophic failure that claimed 11 lives on May 26. The U.S. Chemical Safety Board’s preliminary report indicates the tank at Nippon Dynawave Packaging Company’s Longview facility exhibited dangerous structural deterioration that was never remedied prior to the explosion.

External inspections revealed “significant thinning” of the tank’s walls below safety thresholds in July 2025, with follow-up examinations in October 2025 and February 2026 confirming that large sections remained dangerously compromised. Despite these findings, Nippon Dynawave neither removed the tank from service nor reduced its operating capacity, the board found. The contractor’s inspection explicitly labeled the situation as “Priority 1: Not fit for continued service unless corrected.”

The May 26 rupture released approximately 900,000 gallons of white liquor, a caustic chemical used in wood processing that causes severe burns. The discharge was forceful enough to demolish vehicle structures, breach building walls, and flood lower-level work areas where morning staff meetings were underway. All eight electrical maintenance workers present were killed, along with two mechanical shop employees and one worker in the courtyard.

Applied Technical Services LLC performed the inspections that identified the safety deficiencies. Chemical Safety Board Chairperson Steve Owens stated the agency was “greatly concerned” that the company disregarded clear inspection warnings and failed to take corrective action. The board’s investigation remains ongoing, with a final report forthcoming.

Separately, Washington’s Department of Ecology issued 35 environmental violation notices to Nippon Dynawave this week for air, water quality, and waste compliance failures. Emergency responders treating casualties at the scene were hampered by inadequate hazard communication, as company officials did not initially clarify that white liquor had been released.