A federal investigation is underway at the Longview chemical paper mill where at least nine workers were killed and several injured earlier this week, with two workers still missing and presumed dead.
A catastrophic tank failure at the facility on Tuesday released hundreds of thousands of gallons of a highly corrosive chemical known as “white liquor” that is used to break down wood chips into pulp.
As investigators search for clues to what triggered the disaster, state records show the Nippon Dynawave Packaging Co. mill had a history of worker safety, air and water violations spanning more than two decades – though they appear to be unrelated to the tank rupture.
Brian Wood, a spokesperson for Nippon Dynawave, could not be immediately reached for comment.
Over the past decade, the Washington Department of Ecology – the state’s environmental regulator – issued eight penalties totaling about $41,500 to the Longview mill, with two thirds of the penalties tied to air quality violations.
Most of the air violations involved the mill releasing excessive smoke and air pollution or failing to properly control emissions from boilers and pulping processes, including sulfur dioxide and other harmful gases.
Water quality violations involved releasing excess debris and organic waste into waterways.
Most recently in March, the agency fined the mill $5,500 after it released too much untreated gas into the air over several months in 2024 – gases that are supposed to be captured and treated before being released.
Department of Ecology spokesperson Andrew Wineke said the agency had also issued additional permit violations at the Nippon Dynawave mill that did not result in penalties.
In 2021, Wineke said, the company that runs the Longview mill reported that white liquor from a holding tank had leaked onto the ground and flowed to the nearby storm sewer system. The tank in question was a storage tank outside the main process area, not the tank that ruptured this week.
Mill officials said the spill occurred because a valve was left open “due to employee negligence,” according to a report submitted by the company to the state agency. Approximately 3,000 to 5,000 gallons of white liquor were discharged into the ground, the report said. The tank that imploded this week spilled an estimated 550,000 to 570,000 gallons of liquid.
Wineke said the agency issues air quality and water quality permits for the Nippon Dynawave mill and oversees dangerous wastes at the site under state and federal regulations. This includes oversight of the facility’s spill response and stormwater pollution prevention plans.
The Department of Ecology conducts inspections at this type of industrial facility four to five times a year, Wineke said. Its most recent inspection at the Longview mill was in April of this year, he said.
The Longview mill also was under investigation by the Washington Department of Labor & Industries, which oversees worker safety. The agency’s spokesperson Matt Ross said its staff had done six inspections over the past decade at the Longview mill, including three in the last five years. They were not related to the tank.
The most recent three resulted in a total $3,400 in penalties for not requiring workers to consistently wear masks during the COVID‑19 pandemic, for failing to provide fall protection after a worker was observed on an elevated platform more than four feet above the ground without safeguards and for moving equipment after an employee lost a finger, potentially interfering with investigators’ efforts to determine what caused the injury and how it could be prevented in the future.
Of three other inspections prior to 2021, two from 2018 resulted in no violations and one from 2020 resulted in a citation and $700 fine for workers’ failure to deactivate or lock out equipment before going in to clean it.
In addition, the agency had two open and ongoing investigations before the incident occurred, Ross said. One was opened in March after an anonymous complaint about a valve on an aqua ammonia clarifier tank – again, a different tank from the one that imploded. The other investigation was opened in May after a complaint about a sinkhole created by a failed drain. Inspections can take up to six months and the results are published after they are done, Ross said.
The agency also has now opened another investigation into the tank implosion, he added.
Federal records from a pollution call center indicate other chemical spills have been reported at the mill.
According to the Coast Guard’s National Response Center database, more than 120 incident reports were filed between 1990 and 2026 at the Longview mill. These incidents are self-reported by the company and preliminary in nature; some are followed up on by state investigations – though not all investigations lead to violations or penalties.
Most of the reports involve releases of gases, equipment failures and chemical spills into the Columbia River or stormwater systems – including the roughly 3,000 gallons of white liquor spilled and reported to the call center in 2021 and a separate incident involving 2 million pounds of black liquor spilled from a storage tank in 2020 due to equipment failure, federal records show.
A massive fire at the mill that sent a thick plume of smoke into Clark County and the Portland area in the summer of 2023 burned wood chips and does not appear to have involved chemicals. The fire was ruled accidental and no one was injured. But fire investigators wrote that the blaze might have been “mechanical in nature secondary to the decrease in maintenance on the aging equipment.”
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