The suit was filed in late October in Cowlitz County Superior Court on behalf of the estates of Dillon Miller and Clinton Doran, two of the 11 workers who died when a chemical tank ruptured last May, releasing hundreds of thousands of gallons of caustic chemicals. It seeks undisclosed damages.

What sets the new filing apart is its scope. Named as defendants are Nippon Dynawave Packaging, the mill's operator, along with its U.S. and Japanese corporate parent companies. The suit also targets seven entities associated with timber giant Weyerhaeuser and North Pacific Paper Company, known as NORPAC, which adjoin the mill at the shared industrial site where logs are processed into wood products and consumer paper goods.

Attorneys argue that the companies' physical proximity reflects a deeper entanglement — that they may share responsibility for the systems and workplace culture meant to keep workers safe.

"We're naming everybody that we believe had some contribution to the safety practices," said Derek Moore, an attorney with Bishop Legal representing the families of Miller and Doran.

The suit contends that Weyerhaeuser, which sold the mill to Nippon Dynawave in 2016, bears responsibility because it built the chemical tank in a location that exposed workers to a "catastrophic rupture," Moore said. Attorneys also hope to learn through the discovery process what role NORPAC played in shaping the companies' safety culture, he said.

A Nippon Dynawave spokesperson said the company cannot comment on active litigation but is "committed to approaching this matter with compassion and respect for those affected."

Weyerhaeuser public affairs manager Mary Catherine McAleer said the company's "thoughts continue to be with the families who lost loved ones," while stressing that it has not owned or managed the Longview pulp and paper facility since the sale more than a decade ago. A spokesperson for International Paper, which owns NORPAC, said the company cannot comment on ongoing legal matters.

The new lawsuit follows two others filed on behalf of workers killed in the incident. Last month, Nippon Dynawave moved to dismiss one of them — a suit brought in September by Mackenzie Ammons over the death of her spouse, Jared Ammons — arguing that the company is protected under Washington state's industrial insurance act. The century-old law provides swift compensation for on-the-job injuries through the workers' compensation system but grants employers broad immunity in return.

According to the most recent lawsuit, the fatal spill falls within a narrow exception to that law. Moore said the company's conduct amounts to a "deliberate intention" because Nippon Dynawave knew the chemical tank had been weakened by corrosion and that injury or death was "certain" to occur.

The filings are unfolding as the Longview community continues to reckon with a disaster that claimed 11 lives at one of Southwest Washington's largest industrial employers. The outcome of the litigation could shape how responsibility is apportioned among the cluster of companies that operate side by side on the Columbia River waterfront — and whether the families of those killed can hold any of them accountable beyond the limits of the state's workers' compensation system.