LONGVIEW, Washington – Authorities say 11 workers have died following the rupture of a massive chemical tank at the Nippon Dynawave Packaging Co. paper mill along the Columbia River, in one of the deadliest U.S. workplace accidents in recent decades. The tank, which held more than 500,000 gallons of a caustic chemical mixture used to process wood for paper production, suddenly collapsed on Tuesday morning during a shift change, sending a surge of corrosive liquid through a designated gathering area where employees were awaiting their assignments. Emergency crews, including the Washington National Guard’s 10th Homeland Response Force, rushed to the site to conduct search, rescue and recovery operations as the scale of the disaster became clear. By Thursday, officials had confirmed 11 fatalities and reported that eight other employees suffered injuries ranging from severe chemical burns to respiratory complications caused by exposure to the caustic substances. Search teams had recovered the remains of six of the nine workers initially reported missing, and efforts to locate the remaining victims continued as of Friday, May 29, 2026. Local officials, including Longview fire battalion chief Matt Amos, described the chemical flood as capable of causing immediate and severe tissue damage. Investigators and hazardous materials teams have restricted access to the site while they assess potential environmental impacts on the surrounding area and the nearby Columbia River, and federal and state safety regulators are examining the structural integrity of the failed tank as the mill’s operations remain suspended indefinitely.

Prepared by Emily Rhodes and reviewed by editorial team.