Nippon cleanup begins in Longview, but damaged tank limits recovery

State officials are cleaning the chemical spill from the fatal Tuesday morning tank failure at the Longview pulp and paper mill, as the caustic chemical mixture used in papermaking known as white liquor is impacting recovery efforts at the plant.

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Nine people are missing, and another 10 were transferred to the hospital, including seven injured employees, one injured firefighter and two workers confirmed deceased after the implosion that occurred around 7:15 a.m. at Nippon Dynawave Packaging Co.

Washington state Gov. Bob Ferguson held a press conference at 7 p.m. Tuesday at the mill, then at 1 p.m. Wednesday.

Earlier in the day, Ferguson said he directed the National Guard to be on alert, and that he has closely worked with the state departments of Ecology and Labor and Industries on responses.

Diking system closed to river

Department of Ecology spokeswoman Brittny Goodsell confirmed in a phone interview Tuesday afternoon that the agency's spill cleanup crew had been deployed to the mill.

Goodsell said Nippon officials contacted the state agency right away, and that the Department of Ecology plans to work as long as necessary to monitor impacts to the storm drain system and nearby waterways.

Implosion photo

The city of Longview issued this official photo of the ruptured tank that imploded at Nippon Dynawave Packaging Tuesday. The tank is believed to have been able to hold roughly 900,000 gallons of the caustic chemical mixture used in papermaking known as white liquor. Another 90,000 gallons is believed to still be inside it, rendering the scene unstable for recovery efforts.

The storm drain system connects to a diking system that discharges into the Columbia River. Goodsell confirmed that the diking system's pumps were shut off in response to the spill.

As of Tuesday afternoon, Goodsell said it was not entirely clear where ecology's oversight begins in the incident and where it falls to other agencies at the county level, such as Cowlitz County Emergency Management. The reason, Goodsell said in an email, is that the agency is still gathering information on what happened.

"Until we get all the information, we just don't know," Goodsell said. "This is going to take some time."

Structural damage limiting emergency crews

The tank that imploded could hold 900,000 gallons of white liquor, a mixture of sodium hydroxide, sodium sulfide and sodium carbonate.

That is more than 10 times the initial estimate given at a Tuesday press conference.

At the time, emergency responders believed that the tank held 80,000 gallons of white liquor.

The 4:45 p.m. Tuesday notice from the city of Longview and Longview Fire reports roughly 90,000 gallons could remain in the damaged tank, but was later found to hold no more than 25,000 gallons.

The tank was believed to be unstable, creating hazardous conditions for emergency personnel assisting in the recovery effort. Crews were working to stabilize the area to give responders safe access, but later determined it wasn't as unstable as first expected.

Despite those impacts, the city and fire department report there is no direct threat to the community.

What is white liquor?

The white liquor mixture converts wood into pulp through the kraft process.

The facility predominantly manufactures paperboard used to make paper cups and milk cartons.

Used in the papermaking process, the chemicals along with heat and pressure work to separate the cellulose fibers from wood pulp. According to an article on scienceinsights.org, the mixture can have a highly caustic pH level that can exceed that of household bleach.

Nippon history

Nippon Dynawave plant has about 550 employees and makes about 280,000 tons of bleached packaging paperboard used for packaging liquids, along with other base paper pulp materials used for items such as pet pads, filtration papers, insulated doors and printing paper, according to Nippon Dynawave and the Department of Ecology's website.

The plant is part of a more than 700-acre industrial complex on Industrial Way that, until 2016, was owned by Weyerhaeuser, according to permit information about the plant filed with the Department of Ecology.

Weyerhauser and Nippon had also co-owned, as a joint venture since the late 1970s, the North Pacific Paper Company, or NORPAC, in the same complex. In the 2010s Weyerhaeuser divested itself from the pulp paper business, and Nippon and Weyerhaeuser each sold their stakes in NORPAC to private equity firm One Rock Capital Partners in 2016. Earlier this year, International Paper announced that they are in the process of a $360 million deal to acquire NORPAC.

After 2016, Nippon took on the industrial wastewater treatment plant and has agreements to handle the wastewater of connected businesses such as NORPAC, according to the permit.

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This story was originally published May 28, 2026 at 4:16 AM.