On August 28, 2026, the US Chemical Safety and Hazardous Investigation Board (CSB) issued an update regarding its investigation of a May 2026 tank failure. A 1.2-million-gallon atmospheric storage tank failed catastrophically and released approximately 900,000 gallons of extremely hot highly corrosive fluid, killing eleven and seriously injuring three others.

Prior Notice of Tank Shell Deterioration
CSB’s news release said it discovered that an inspection of the tank’s exterior shell 10 months before the incident reported “significant portions of the tank’s carbon-steel shell had thinned below the calculated minimum safe thickness.” The inspection contractor’s report recommended the company “internally inspect and repair the identified thinned areas.” The contractor also informed the company that the tank was not fit for continued service and posed a “high likelihood/consequence of failure.”

Upset Caused the Tank to Fill to Near Capacity
A CSB Supervisory Investigator, quoted in the news release, suggested the tank may have been safe to operate at reduced conditions. Indeed, on the day of the incident, the tank was operated significantly below full capacity. An upset at a downstream location prevented the ongoing removal of fluid from the tank, although the tank continued to receive hot corrosive fluid from an upstream process. The tank failed catastrophically when filled to 90% of capacity.

CSB’s investigation will continue and more updates may precede its final report. CSB makes its updates and reports publicly available. It does not issue citations or fines but makes safety recommendations to companies, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA.

To see the news release, which has a link to the full update https://www.csb.gov/us-chemical-safety-board-issues-update-on-investigation-into-the-fatal-catastrophic-tank-failure-at-the-nippon-dynawave-packaging-facility-in-longview-washington/