Nippon Dynawave Packaging Co. sits on the Columbia River, in Longview, Wash., on May 27, 2026. Contamination entered the river following the plant’s chemical disaster, but state officials quickly worked to control further contamination.
Eli Imadali / OPB
It’s been less than a week since the rupture of a massive tank spilled hundreds of thousands of gallons of caustic chemical at a Longview, Washington, paper mill. Some of those likely killed in the workplace disaster Tuesday have yet to be recovered.
Yet pressure is mounting for answers from the company and government officials, even as they caution an investigation will take time. Investigators from the U.S. Chemical Safety Board arrived on site Wednesday.
“We are cooperating fully with the agencies that have the responsibility to the public to do that analysis,” said Brian Wood, director of support services for Nippon Dynawave and a city councilor in nearby Kelso. “It would be very premature to try to estimate when that might be available. We are very much in early days.”
Some family members of victims in this industrial pocket of Southwest Washington have started calling for answers and publicly questioning the safety culture at the pulp mill, and at least one family has retained an attorney. Wood has defended the company’s safety record during press conferences.
People hold pictures of their family members still unaccounted for during a vigil for the victims of the Nippon Dynawave Packaging Co. chemical implosion at R.A. Long Park in Longview, Wash., on May 26, 2026.
Eli Imadali / OPB
Josh Estes, head of the local chapter of the Association of Western Pulp and Paper Workers union, said recovery efforts should remain the top priority until they are done. But he understood why some families’ focus is starting to shift towards accountability.
“We are going to fight to get those answers,” he said.
OPB spoke to seven chemical safety experts and former investigators about what officials would look for to determine how the rupture happened and what could have prevented it.
Those experts said Washington state’s deadliest workplace incident in nearly a century likely resulted from a complex mix of factors — the tank itself, the chemical involved, potential issues with vents — combined with a terrible coincidence of timing. The implosion happened at about 7:15 a.m., during a shift change that brought more workers on site and around a break room that was located next to the massive tank of deadly chemicals.
“Sometimes we might find things that have been overlooked,” said Johnnie Banks, who was a federal chemical investigator for more than a decade. “It’s usually not one thing overlooked, but multiple things happening in concert on a given day and a given time when things go bad.”
Soldiers and airmen from the Washington National Guard’s 10th Homeland Response Force offer support to first responders following an rupture of a chemical tank at Nippon Dynawave pulp and paper mill on Thursday, May 28, 2026, in Longview, Wash.
Adeline Witherspoon / Adeline Witherspoon/Washington National Guard via AP
‘Nasty material’
The pulp mill along the Columbia River in Longview has been using a chemical stew to cook wood chips for more than 70 years. The process itself is even older.
Known as kraft pulping, it disintegrates the wood into a strong cellulose material that can be used to make paper or containers like milk cartons.
“You have probably cooked meat or something in a pressure cooker, right? Well, it’s the same,” said Julia Shamshina, a professor at Texas Tech with the Fiber and Biopolymer Research Institute in Lubbock. “You put wood into the pressure cooker, you put in a bunch of chemicals in the pressure cooker, you close it, you heat it up and you cook under the pressure.”
The chips are heated with a cocktail of sodium hydroxide, or lye, and sodium sulfide to make the caustic chemical known as “white liquor.”
“White liquor is a nasty material,” said Stephen Kmiotek, professor of chemical engineering at Worcester Polytechnic Institute. “Highly, highly corrosive, pH of 14, very subject to chemical burns.”
There are about 4,500 active pulp and paper mills across the world, according to a research paper Shamshina co-authored. The majority of them are located in Asia, with only about 128 paper mills still operating in the United States.
Reported incidents involving “white liquor” are rare. Before Tuesday, there had been only eight spills in the past 10 years across the country, according to an analysis of National Response Center data.
One of them was also at Nippon Dynawave in 2021, when 3,000 gallons of it leaked from an open valve. None of those incidents resulted in injuries.
Experts say that pulp and paper-making processes have changed little in the past 100 years, including the fact that they’re extraordinarily dangerous.
Collapsed like a water bottle?
Kmiotek, who spent decades as a chemical engineer and has closely tracked the Longview disaster, said photos of the tank suggest it collapsed inward instead of exploding and propelling outward. He said a dramatic change in pressure could cause a catastrophic implosion.
It’s possible that a relief valve on the top of the 900,000-gallon tank could have become plugged, he said, causing the tank to collapse in on itself.
“Picture a plastic water bottle, those real thin-walled plastic water bottles and you put your mouth over it and start drinking, but you have a good seal on that opening,” Kmiotek said. “And so it collapsed just like that water bottle.”
Unlike industrial tank explosions, which he said “unfortunately are quite common,” Kmiotek could count on one hand the number of tank implosions he’s seen in 40 years of practice.
Aerial views of the Nippon Dynawave Packaging Co. in Longview, Wash., showing the scene of a major chemical tank rupture at a Southwest Washington paper mill, May 26, 2026.
Brandon Swanson / OPB
“If I had to guess, there was some blockage,” Kmiotek explained. He said he’s talked to a half dozen colleagues who have all come to the same conclusion. “There was no way for air or something else to backfill that volume as they were sucking material out of it.”
Investigators will examine the construction of the tank for cracks or corrosion or venting problems, Banks, the former chemical investigator, said. They will comb through maintenance records to find potential equipment errors. They will interview employees, managers and engineers to determine causation and issue recommendations on how to prevent future accidents.
“There was something dramatically wrong with the tank that caused it to rupture or collapse,” John Bresland, former chair of the U.S. Chemical Safety Board, the agency investigating the Longview incident, told OPB.
The Longview plant requires routine inspections of its tanks. Since 1998, it has kept a plan on file with the Department of Ecology. The company conducts routine testing of its systems and files reports with the agency.
The most recent version of the plan, updated in June 2025, states that liquor storage tanks “are scheduled for visual external inspection annually.” Additional testing, such as internal inspections, “are scheduled for some tanks where deemed appropriate based on individual tank design and operating characteristics.”
Marissa Baker, a professor with the University of Washington’s Department of Environmental & Occupational Health Sciences, said all workplace injuries should be considered preventable, and it’s the responsibility of companies to protect their workers.
“You’re dealing with massive amounts of chemicals,” she said. “What happens if it falls? What happens if it explodes? They have probably thought through quite a bit what would happen if it explodes, if the heat or the pressure. Those are things that are monitored. Those are things that are checked.”
Baker said it was notable that Nippon Dynawave had three inspections in five years and two open inspections at the time of the tank rupture. One involved a valve on an aqua-ammonia clarifier tank. The other was opened in May after a complaint about a sinkhole, which was created by a failed drain.
Nippon Dynawave has sustained a few fines in the past five years from the Washington Department of Labor and Industries. Investigators found employees not wearing face coverings during the COVID-19 pandemic in one case and also found a platform higher than four feet that lacked guardrails.
A worker also lost a finger last year. Investigators cited Nippon Dynawave for failing to keep equipment in place until an inspector could arrive to investigate.
Combined, Nippon has incurred $3,400 in fines from workplace investigators since 2021.
Nippon Dynawave Packaging support services director Brian Wood speaks during a press conference at the Nippon Dynawave Packaging Co., where a chemical disaster occurred May 26 at the Longview, Wash., plant for kraft pulp, paper mill and liquid packaging on May 27, 2026. Washington Gov. Ferguson called it the “deadliest industrial tragedy in modern Washington state history.”
Eli Imadali / OPB
“If you keep having problems such that you’re on L&I’s radar or you have problems such that your employees are reporting you, there’s probably something that can change to create a better health and safety culture on that site,” Baker said.
Speaking to reporters Thursday, Wood defended Nippon Dynawave’s safety.
“We work in a highly hazardous atmosphere and a highly hazardous industry,” Wood said. “We approach it with the utmost care in everything that we do. I’ll let the facts speak for themselves.”
Kmiotek said while it is the company’s responsibility to take reasonable precautions to keep workers safe, they can’t account for everything that might go wrong.
“At the end of the day, there’s going to be some bad things that happen,” he said.
‘Business as usual — at the worst time’
For the Longview mill, Jeff Wilson was one of those precautions.
He serviced the mill’s boilers and tanks under its previous owner, Weyerhaeuser, before he sold his hazardous materials clean-up firm Cowlitz Clean Sweep in 2016. His home’s backyard is sculpted by one of the many ditches that sponged up Tuesday’s white liquor runoff.
Washington State Sen. Jeff Wilson poses for a portrait at his Longview, Wash., home three days after the Nippon Dynawave Packaging Co. chemical disaster in Longview, Wash., on May 29, 2026. Wilson used to contract with Nippon Dynawave and his son currently works there.
Eli Imadali / OPB
Wilson has stood many times in the courtyard where the tank spilled. He has even crawled inside the tank itself.
“This tank doesn’t seem anything other than normal,” he said, other than its immense size. It perches over a courtyard that includes a vast humming boiler that makes the mill itself feel alive. “Steam, the sound, the boiler working — it’s all part of the mill atmosphere.”
Wilson is now a state Senator representing Longview and a commissioner at the Port. Sitting on his back patio, the 66-year-old slumped his shoulders while considering how many things went wrong to cause the calamity just two miles south of his home.
As a hazmat contractor, Wilson responded to an array of emergency calls at the now Nippon-owned mill. He had helped clean up white liquor in the past, as well as the similarly dangerous green liquor and black liquor chemicals. Most often, however, he cleaned up less-toxic pulp spills.
Those hazards often stemmed from either technology failures or human error, he said. He defended the mill’s safety protocols and suspected the cause of the rupture is linked to failed equipment.
“It inherently comes with hazards and people are not novices,” Wilson said.
In the same breath as he defended Nippon’s safety protocols, Wilson said human error can be deadly in industrial work. Years ago, at the Nippon site, Wilson witnessed a contractor driving a snorkel lift, operating it via controls in a bucket several feet in the air. The contractor hit a gas line that quickly caught fire, Wilson said. It burned so hot it melted the bucket and killed the contractor.
A detail that stuck out to Wilson about Tuesday’s tank rupture is the unfortunate timing that it happened during a shift change. The corrosive wave knocked down multiple walls. A break room was caught in the disaster.
“It was business as usual — at the worst time,” he said. “That was probably the biggest quantity of people that would be there at any one time because of the shifting.”
OPB’s Joni Auden Land and Tony Schick contributed reporting.
