How a chemical tank disaster struck at the heart of a Washington state mill town

From his living room, Washington state Sen. Jeff Wilson watched Nippon Dynawave Packaging Co.’s chemical tank rupture in Longview, killing 11 people. The tank held more than 500,000 gallons of a caustic mixture used to break down wood for paper, and its collapse Tuesday morning sent a flood of chemicals that overturned pickup trucks and damaged structures at the site. The last of the victims was identified on Saturday, ending a tragedy that has struck at the heart of a town whose economy once depended on mills. Nippon Paper Group said it is assessing the disaster’s impact on its finances.