A 900,000-gallon white liquor tank ruptured at Nippon Dynawave’s Longview mill on May 26, killing 11 workers. The cause remains under investigation.
Before it failed, Washington agencies had reviewed the facility for pollution and workplace-safety issues. But state regulators told me they did not inspect the failed tank or review its structural inspection, maintenance, engineering or hazard-assessment records.
The company may have inspected the tank internally or hired private contractors to do so. Nippon Dynawave has not answered questions about when the tank was last inspected, who inspected it or what those inspections found.
‘Outside the scope’
The Washington Department of Ecology said it has no inspection records for the failed tank.
“Other than the spill control and stormwater pollution prevention plans noted previously, the agency does not regulate white liquor tanks,” Andrew Wineke, the agency’s deputy communications director, wrote in an email.
The Washington Department of Labor and Industries, the state’s workplace-safety agency, said prior inspections at Nippon Dynawave, going back to 2016, focused on other safety issues.
Reviewing structural inspection, maintenance, engineering or hazard-assessment records for the failed tank “would have been outside the scope of what we were there to look at,” L&I spokesperson Matt Ross wrote.
Ross said Nippon Dynawave still had a legal duty to address tank risks.
“State law in Washington requires every employer, including pulp and paper mills, to assess the unique hazards on their job site and make sure they are taking steps to address them to keep their workers safe on the job,” Ross wrote. “That includes tanks like this one.”
Separate problems, separate reviews
In May 2025, records say a pressure-relief valve opened during a process startup at Nippon Dynawave and released a mist of black liquor, another caustic chemical used in pulp production. Ecology reviewed the incident because of its environmental implications.
L&I said it was not aware of the release before the fatal rupture.
“No workers were injured, so there was no requirement to report it to L&I, and we did not receive complaints or referrals related to it,” Ross wrote.
L&I also opened two complaint-based inspections at Nippon Dynawave in the months before the rupture. One involved a valve on an aqua ammonia clarifier tank. Another involved a sinkhole created by a failed drain.
Ross said neither complaint involved the physical area near the failed white liquor tank.
Investigators have not determined what caused the tank to rupture. Marissa Baker, an associate professor at the University of Washington’s Department of Occupational Health Sciences, cautioned against linking earlier incidents to the disaster before the root cause is known.
But Baker said employers are responsible for managing known workplace hazards, whether or not a government inspector checks the equipment.
“Certainly having a large tank holding such a hazardous chemical is something that would need to be maintained and inspected to ensure safe working conditions for individuals at the site,” Baker wrote in an email. “However, the impetus is on the employer to figure out how to do that.”
The U.S. Chemical Safety Board and L&I are investigating the rupture. Their findings are expected to determine whether Nippon Dynawave inspected, maintained and assessed the tank before it failed, and whether those efforts met the company’s duty to protect workers.
Legislative response
Joshua Estes is a spokesperson and lobbyist for the Association of Western Pulp and Paper Workers, known as AWPPW, which represents mill employees. He told me he is “not aware of any recent legislative efforts specifically focused on independent inspections or mechanical integrity requirements for the type of tank involved in this incident.”
But that may soon change.
State Sen. Jeff Wilson, R-Longview, said he is drafting legislation aimed at large above-ground caustic tanks, including possible independent inspection or recordkeeping requirements.
Wilson said he hopes to prefile a bill in December, before the next legislative session. He said the failed tank appears to have been built in the early 1990s, though Nippon Dynawave has not confirmed its age.
Oversight of tanks like it appears “to potentially be self-certification by the industry owner-operator of the facility,” Wilson said.
Baker warned that new legislation would not be a quick fix. Lawmakers could direct L&I to examine new tank rules, she said, but formal rulemaking can take years and would likely require public hearings, industry input and analysis of costs and feasibility.
She also cautioned against treating the disaster mainly as a failure of government regulation. Washington law already requires employers to assess and control recognized workplace hazards, she said.
“I don’t want this to become a, ‘This is an L&I problem, we should be regulating this,’” Baker said. “How about instead we hold employers, owners, operators accountable for incidents that happen on their work sites?”
Estes said the AWPPW has spoken with Wilson multiple times since the rupture and has worked with him on policy issues before. He said no formal legislative proposal has been presented to the union, which is focused, for now, on supporting workers and families and letting investigators determine what happened.
“Senator Wilson has made it clear that the voices of workers and their representatives must be part of any policy discussion that may result from this incident,” Estes wrote in an email. “He has assured us that the AWPPW, along with other critical stakeholders, will have a seat at the table and be actively engaged in any future conversations regarding potential legislative, regulatory or industry changes.”
Last Updated on June 16, 2026 by Joe Douglass
