Remote Surveillance Trailer in Longview, WA

CSB Discovers that Nippon Dynawave Packaging Company Was Told in July 2025 that the Tank Was Not Fit for Continued Service and Could Fail

Washington, D.C., August 28, 2026 — The U.S. Chemical Safety and Hazard Investigation Board (CSB) today released an update on its investigation into the deadly May 26, 2026, catastrophic failure of a 1.2-million-gallon atmospheric storage tank at the Nippon Dynawave Packaging Company, LLC (NDP) pulp and paper mill in Longview, Washington. The tank (identified as G Tank) released approximately 900,000 gallons of extremely hot highly caustic white liquor, fatally injuring 11 NDP employees and seriously injuring three others.

The CSB’s investigation found that an inspection of the exterior shell of G Tank conducted in July 2025 -- approximately 10 months before the fatal incident -- identified that significant portions of the tank’s carbon-steel shell had thinned below the calculated minimum safe thickness.

The inspection contractor’s report recommended that NDP internally inspect and repair the identified thinned areas of G Tank’s shell. The inspection report also stated that G Tank was “[n]ot fit for continued service” unless it was repaired and that there was a “[h]igh likelihood/consequence of failure”. Despite the inspection’s findings, G Tank remained in service until it catastrophically failed on May 26, 2026.

NDP conducted additional external inspections of G Tank in October 2025 and February 2026. Both inspections also determined that substantial portions of G Tank’s shell remained thinner than the calculated minimum safe thickness. Even after these additional inspections, NDP still did not internally inspect or repair the tank shell, remove it from service, or reduce its operating conditions before it failed.

CSB Chairperson Steve Owens said, “Although the CSB’s investigation is still ongoing, we are greatly concerned that the tank was not promptly removed from service or properly repaired after the clear findings in the inspection report.”

CSB Investigator-in-Charge Drew Sahli explained, “The minimum safe thickness is the amount of material necessary for an atmospheric storage tank to safely contain its contents. G Tank’s shell had areas thinner than the minimum thickness required for continued service at its typical operating conditions.”

CSB Supervisory Investigator Mark Wingard said, “The inspection identified significant tank-wall thinning below the minimum safe thickness months before the failure. Our investigation is examining why the tank remained in service without either being repaired, or operated under reduced conditions.”

On the day of the incident, May 26, 2026, a process upset required NDP to stop sending white liquor from G Tank to the digestor at the mill where it would have been used to produce pulp from wood chips. However, even though no white liquor was leaving G Tank, white liquor continued to enter the tank from the recausticizing process at the mill, causing the tank level to rise to approximately 90 percent full by 6:22 a.m.

As shown in recently released surveillance footage, at approximately 7:09 a.m., G Tank catastrophically failed, rapidly releasing approximately 900,000 gallons of the scalding hot (200° F) highly corrosive liquid, flooding the surrounding courtyard and nearby buildings where employees were gathered for morning meetings. Eleven NDP employees were fatally injured, and three were seriously injured by the release. Five additional NDP employees and one firefighter sustained injuries but did not require inpatient hospitalization.

CSB Board Member Sylvia Johnson said, “The CSB’s investigation will determine the events that led to the tank remaining in service and our investigation will seek to determine how future incidents can be prevented.”

The CSB continues to investigate the causes and contributing factors associated with the failure, including NDP’s mechanical integrity, inspection and maintenance practices; NDP’s actions to inspect, repair, and/or replace G Tank and other atmospheric storage tanks in light of G Tank’s deteriorated condition; operating conditions preceding the failure; NDP’s emergency response policies and procedures; and regulatory requirements and industry guidance.

The CSB is an independent, nonregulatory federal agency charged with investigating incidents and hazards that result, or may result, in the catastrophic release of extremely hazardous substances. The agency’s core mission activities include conducting incident investigations to identify root cause of releases; formulating preventive or mitigative recommendations based on investigation findings and advocating for their implementation; issuing reports containing the findings, conclusions, and recommendations arising from incident investigations; and conducting studies on chemical hazards.

The agency's board members are appointed by the President subject to Senate confirmation. The Board does not issue citations or fines but makes safety recommendations to companies, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA.

Please visit our website, www.csb.gov. For more information, contact Director of External Affairs Hillary Cohen at Hillary.Cohen@csb.gov.

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Employees at the Nippon Dynawave paper mill described the chemical tank in interviews with investigators. One stated it was “not in good working condition.”

The chemical tank that collapsed in late May, killing 11 people at a paper mill in Longview, Washington, was being worked on and scheduled for replacement at the time of the incident, according to statements from staff at the facility released by the Cowlitz County Sheriff’s Office.

Multiple employees of Nippon Dynawave Packaging Company questioned by sheriff’s deputies in the aftermath of the company’s tank rupture said they noticed scaffolding around the tank, indicating some work was being done on it. According to the documents, a maintenance supervisor at Nippon Dynawave told a deputy the tank “was scheduled to be replaced sometime next year.”

The exact reasons why the 900,000-gallon chemical tank was being serviced and slated for replacement are unknown. One employee said the scaffolding was related to insulation being put into the tank.

Several employees questioned by sheriff’s deputies said they had not been aware of any safety issues with the tank prior to its collapse. Others said the tank was “not in good working condition” and that they’d heard the tank had recently failed an inspection.

One employee told the sheriff’s department the tank was designed to hold a less corrosive chemical than the white liquor that burst out of it on the morning of May 26.

“Obviously, when you have a disaster like this and the loss of life like this, something went wrong,” Washington state Attorney General Nick Brown told OPB in a July interview. Brown’s office took over an investigation from the Cowlitz County prosecuting attorney’s office.

“When you have such a scale of mistakes or errors or whatever led to this tragedy, it obviously belies that a review needs to be done,” he said.

State and federal agencies are still investigating the cause of the tank failure. The investigatory documents describing the early hours of the incident were released to OPB from the sheriff’s office as part of a public records request. They were

Nippon Dynawave spokesperson Sam Jefferies declined to comment when asked about the statements from paper mill employees about the tank’s condition and scheduled replacement. He said in a written statement the company is supporting the independent state and federal investigations that are currently happening.

“At this time, we will not speculate about the root cause without the full facts. Doing so would be a disservice to our committed employees and to the families still mourning the loss of their loved ones,” he said in the statement.

A “loud rumble”

Shortly after 7:00 a.m., on the morning of May 26, employees of the paper mill gathered in a breakroom during a regular morning briefing. Mark Massey, a supervisor at the mill, told deputies he heard a “loud rumble” before the highly corrosive white liquor, used to break down woodchips, poured into the room.

“As others and himself were trying to escape he heard lots of yelling and screaming behind him,” Cowlitz County Sheriff’s Deputy Jesse White wrote in a report.

Nicholas Dykstra, a member of the mill’s mechanical crew, described being inside the breakroom as the accident unfolded to Detective Jason Hammer.

“Dykstra heard scaffolding outside start to break and fall, and he knew there was a problem with the holding tank,” Hammer wrote.

“Trust has been violated”

Agencies ranging from Washington State Labor and Industries to the state Attorney General’s office are now investigating the cause of the paper mill disaster, which Washington Gov. Bob Ferguson has called the “deadliest industrial tragedy in modern Washington state history.”

An initial assessment describing the known facts of the incident is expected from the U.S. Chemical Safety and Hazard Investigation Board.

Families of victims and workers impacted by the incident have retained attorneys. Vanessa Waldref, who formerly served as U.S. Attorney for the Eastern District of Washington, is representing three workers who were impacted by the accident.

“These employees, these workers, the community, trusted Nippon Dynawave to keep this workplace safe for everyone in the community,” Waldref said. “That trust has been violated.”

Both Waldref and Brown said investigations into incidents with this level of complexity move slowly.

In the meantime, some of the mill’s employees have begun to return to work. Others are still on paid leave as those investigations run their course. The company agreed to continue paying furloughed employees through Oct. 11.

Editor’s Note: A video was removed from this article because it was not authorized for use.

PORTLAND, Ore. (KOIN) – Federal investigators say the that ruptured in May was unfit for service before the deadly failure, and Washington leaders want answers.

The Friday saying the tank in Longview was unfit 10 months before the rupture . In response, Washington Sen. Patty Murray called for accountability from Nippon Dynawave.

“Three months ago, Longview endured an unthinkable tragedy and suffered enormous loss,” Murray said. “This community deserves answers and the release of today’s investigation update is an important first step towards understanding exactly what happened so we can ensure that there is accountability and that a tragedy like this can never happen again.”

According to the report, the company continued operating the tank without making repairs, despite three inspections from an outside contractor that recommended them.

“The Chemical Safety Board’s update revealed that Nippon Dynawave knew that the walls of the chemical tank that failed were dangerously thin. The investigation is ongoing, and I am appreciative of the important work that the CSB is doing to get the clarity we need,” Murray said. “We know this will take time—but one thing is apparent: this community deserves answers and accountability. Every worker has the right to come home safely at the end of the day. I will continue to follow this investigation closely, and I will be there every step of the way to support this community.”

The from Nippon Dynawave’s spokesperson Sam Jefferies saying the company would not comment on the findings due to ongoing litigation.

“Our focus remains on supporting affected families and employees and taking the necessary steps toward fully reopening the Longview facility,” Jefferies said in the email to AP.

The Association of Western Pulp and Paper Workers union also shared a statement following the release of the report. It it viewable in the document below.

This announcement comes after Washington’s Department of Ecology for dozens of environmental violations.

Stay with KOIN 6 News as this story develops.

Plaintiffs filed the lawsuit in 2024 after the city manager was fired, claiming four councilors met in private to plan her ouster.

A two-year legal fight involving the City of Longview, Washington, has finally come to a close with an $80,000 settlement agreement.

The settlement, which the city council unanimously approved during a Tuesday meeting, will go toward attorney fees for three plaintiffs, who sued the city after its elected officials abruptly fired their top administrator in April 2024.

The case raised questions about whether local government officials worked together behind closed doors in violation of state transparency laws. It ratcheted up city legal bills and sparked personal attacks on city councilors, they said at the meeting. Now, the city is moving on by paying legal fees — without committing to concrete policy changes or admitting any wrongdoing.

The plaintiffs include residents Thomas Samuels, John Melink and former councilor Mike Wallin. Melink declined to comment on the details of the settlement until it’s finalized.

Their lawsuit alleged three current councilors — Erik Halvorson, Kalei LaFave and Keith Young, as well as former Mayor Spencer Boudreau — violated Washington’s Open Public Meetings Act by planning former City Manager Kris Swanson’s firing out of public view.

The councilors have consistently denied violating the law. The case had been slated to go to trial in September.

“Even if we went to trial and we won, the cost to the city would be far, far more than this,” Young said during Tuesday’s meeting.

The agreement brings the total bill in the case, footed by Longview taxpayers, to more than $250,000, according to a city spokesperson. Most of that comes from Longview’s legal defense costs. In May 2024, a Pacific County Superior Court judge ordered the city to cover the legal fees for the three councilors and the now-former mayor, who lost his reelection bid in 2025.

As part of the settlement, the city will “consider reviewing its public records act policy” and “develop a cell phone issuance policy for elected officials” for council consideration, according to a summary of the settlement in the meeting agenda.

LaFave and Halvorson both said at the meeting that the case impacted them professionally and personally, leading to insults from constituents and causing sleepless nights in the two years since the lawsuit was initially filed.

Ruth Kendall, one of the councilors who voted against firing former City Manager Swanson, said the whole saga has been a good reminder of the importance of the open meetings law.

“When it appears that decisions have been made outside of council meeting, it isn’t a good feeling,” Kendall said in an interview. “You do not feel empowered as a member of that council.”

She said it’s nice to see the council moving forward, and that the settlement is an opportunity to put this case in the past.

“Other cities — what we’ve gone through — should be a lesson to everybody,” she said.

The settlement agreement is pending final signatures from all parties and a judge.

LONGVIEW, Wash. (KATU) — Firefighters in Longview spent Saturday battling a large scrap pile fire at a recycling center, with officials urging all businesses and residents nearby to stay indoors.

The large fire was reported at PNW Metals, a recycling center in Longview, Washington around 12:30 Saturday afternoon.

The Longview Fire Department and Cowlitz 2 Fire & Rescue responded to the site.

Residents and businesses in nearby neighborhoods were urged to stay indoors, keep windows and doors closed, and avoid breathing the smoke whenever possible, as crews worked to calm the fire.

People with respiratory conditions, asthma or other health concerns were advised to take extra precautions and remain inside until conditions improve.

Around 2:45 p.m., the Cowlitz County Department of Emergency Management said in a post on social media that fire officials were emphasizing that residents in the area of the Port and the Highlands neighborhood should avoid the smoky conditions and shelter in place inside their residence.

The department also said residents should close windows and air intake systems as needed.

Travis Weighall used to work at the recycling center and said the pile is likely scraps of tires, metal, and furniture like car seats.

"The smoke's kind of got me worried because of the chemicals that are in it right now," he said.

Correy Watson lives just blocks away from the recycling center and said the first thing he noticed was a horrible smell.

"Then I came outside, I looked up, and I [saw] a bunch of smoke," Watson said. "So I, being curious, I kind of looked over there 'cause that's where most of it's coming from, [and] all I see is black smoke."

He went on to say, "I was trying to get my kids in the house, and as soon as I stepped out of the backyard, my backyard was just covered in smoke and I could barely talk without coughing."

Larry Hembree of the Cowlitz County Department of Emergency Management said, “Citizens, especially those with respiratory difficulties, are encouraged to avoid areas of smoke throughout the Longview/Kelso area, from the Industrial Fire near the Port of Longview. It is strongly encouraged that citizens do not attempt to drive to the fire area or attempt to drive through the smoke!”

Hembree said Longview Fire and Cowlitz 2 Fire & Rescue were dispatched at approximately 12:30 this afternoon to an industrial fire involving scrap metal. He said fire units on scene asked that residents remain aware of the direction of the smoke, which “has shifted with the winds from West to North to Northeast and back to West, throughout this fire.”

“This is expected to be a long duration event,” Hembree said. “Updates will be posted as necessary.”

Around 10 p.m., Longview Fire Department provided an update on social media that the Washington State Department of Ecology tested air quality with results showing no areas of concern. The department also said it worked with City of Longview Public Works and CDID1 to turn off diking district pumps and ensure no discharge went into the Columbia River.

"Fire fighting water and run off remains on site and in CDID 1 ditches," the social media post read. "PNW Metal and CDID 1 will coordinate future testing as needed."

While PNW Recycling is still investigating what caused the fire, Weighall said it's likely the material generated enough heat on its own to eventually combust and start a fire.

The extent of the fire's effect on Oregon is currently unclear. The recycling facility sits just across the Oregon town of Rainier.

Officials said it is recommended to shelter in place if smoke from the fire is affecting your neighborhood, and additional updates were expected.

The owner of a convenience store called Deli Store and More in Rainier told KATU News that while they can see the smoke and smell it, the smoke did not appear to be heading towards the town.

Oregon's Columbia County Emergency Management told KATU News they are aware of the fire, but not issuing any advisory or warnings at this time because the smoke is not moving over the river. The county said it will announce any changes.

KATU News crews out on in Longview said the fire smells like rubber and chemicals.

KATU News is reaching out to several officials from both states for more information, including on the type of smoke produced from the fire and potential health impacts.