Nippon Dynawave performed no inspections or repairs after July 2025
The U.S. Chemical Safety Board released an update Friday showing that an inspection contractor had found a chemical tank at the Nippon Dynawave Packaging Company paper mill in Longview, Washington, “not fit for continued service” 10 months before it failed, according to the board.
The contractor conducted the inspection at the facility in July 2025 and recommended internal inspections and shell repairs on the tank, according to the board’s findings. Nippon Dynawave performed neither the recommended internal inspections nor the shell repairs in the 10 months that followed, the board found.
The tank ruptured on May 26, releasing enough caustic liquid to blow out building walls at the mill. Eleven workers were killed, making it one of the deadliest U.S. workplace incidents in recent decades.
The board said it has not yet determined the cause of the failure as part of its ongoing investigation.
An email seeking comment was sent to Nippon Dynawave Packaging Company on Friday. A person who answered the phone at Nippon’s plant in Longview declined to comment, and a message was left seeking comment.