Nippon white liquor exposure explained as responders face contamination risks

The people recovering bodies and cleaning up the site at Nippon Dynawave in the aftermath of Tuesday’s deadly tank rupture have safeguards that include ventilators and strict decontamination protocols.

But they’re working through hazardous conditions that include heavy structural damage and large quantities of a highly caustic chemical that burns on contact.

The Tuesday morning rupture of the chemical tank caused the “rapid outflowing” of a papermaking material known as white liquor, which blew out several walls in the machine shops in that area and heavily damaged other pieces of equipment, according to Brian Wood, Nippon Dynawave’s director of support services.

“That remains the damage as far as I know,” Wood said at a Friday afternoon press conference.

It’s not yet known if the tank failure was caused by an explosion or an implosion. The tank had a capacity of 900,000 gallons and was roughly 90% full, officials have stated in earlier updates on the Washington State Department of Ecology’s incident page.

For comparison, an Olympic-size swimming pool holds 660,000 gallons of water.

Hazards of white liquor

According to Marissa Baker, director of the Industrial Hygiene Program at the University of Washington, white liquor contains chemicals that are highly caustic and capable of severe chemical burns when exposed to skin and eyes.

On-site, workers are facing that residue on equipment, debris and more.

“They’re trying to spray the water to neutralize it, but anything they would potentially touch, they have to assume could have that white liquor on it,” Baker said.

Additionally, there are inhalation exposure risks for anyone moving debris, and the spraydown of surfaces and materials also threatens to generate aerosols or mists.

“And that could also be an eye irritant or an irritant of the respiratory tract,” Baker said.

White liquor can also generate hydrogen sulfide gas when it reacts with acidic materials. Baker said the gas needs to be monitored closely because it can displace oxygen in high enough amounts.

“This is something that is being monitored for extremely aggressively, and has not been a concern as of yet, but it’s something to think about,” Baker said. “It can cause pretty immediate death with very limited warning.”

A slow process

These exposure risks occur while working around extensive physical hazards, such as unstable structures, damaged pipes and the risk of falling material, as well as confined spaces.

Longview Battalion Chief Matt Amos said at the press conference that crews Thursday and Friday began mitigating hazards that allowed them to move “tighter in the scene” by a matter of “hundreds of feet” but he said the response remains a “slow and meticulous process.”

“There’s still a lot of industrial hazards,” Amos said.

An exclusion zone remains outside the tank, and crews are working to preserve as much as they can for future investigations.

“I know it seems slow, but it needs to be for everybody,” Amos said.

Battery-operated air respirators

The specific protective gear used varies depending on the scenario, according to Baker, but the guidelines follow OSHA’s Hazardous Waste Operations and Emergency Response, or HAZWOPER.

In situations where conditions are not fully characterized, Baker said that emergency officials opt for advanced levels of protection, such as using full-face self-contained breathing apparatuses.

As the response goes on, they may switch from oxygen tanks to suits that use battery-powered respirators that pump filtered air. Other gear deployed on the scene includes chemical-resistant splash suits and alkaline-resistant gloves.

As important as the gear is, the decontamination process is similarly important.

“There’s a closely controlled process we call doffing,” Baker said, describing careful removal of equipment, holding workers in a clean area and regular medical examinations to ensure they haven’t been exposed.

Other challenges and concerns include the use time of equipment. The self-contained breathing apparatus may have only 30-60 minutes of air. And powered air-purifying respirators rely on battery cartridges and filters that must be replaced on schedule.

“I think what’s important to stress is we have the tools to protect these workers, we have the PPE,” Baker said. She added that she urges first-responders not to ignore the signals to change out their equipment.

The last hazard Baker advised first-responders to be mindful of is trauma. Baker said she is involved in studies about stress and mental health in different high-risk industries.

“Everybody responds to trauma in different ways, and it’s OK to honor how you feel and step back when you need to step back,” Baker said.

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This story was originally published May 31, 2026 at 4:38 AM.