Multiple people have been killed and several more are missing after a chemical vat imploded at a paper mill in Washington state.
Nippon Dynawave Packaging in Longview confirmed that several workers died when the toxic tank burst at 7.15am Tuesday.
Mike Gorsuch, battalion chief with the local fire department, described what he saw as a 'mass casualty scene.'
Several more people are believed to have been taken to hospital with severe injuries, including burns and inhalation damage.
Cowlitz Fire and Rescue Chief Scott Goldstein said it was unclear how many employees had been killed.
Asked how many were missing, he replied at a news conference: 'We have information on that, but we're not releasing that information.'
Several distressed relatives waited at the company's visitor entrance later on Tuesday, seeking information about loved ones who worked at the facility.
Nippon Dynawave Packaging facility is a pulp and paper mill and liquid packaging plant that makes material for tissues, printing paper, cups, plates, cartons and other goods.
Multiple people have been killed and several more are missing after a chemical vat imploded at a paper mill in Washington state. The tank contained a chemical brew known as 'white liquor,' a corrosive substance that consists mainly of sodium hydroxide and sodium sulfide
Photographs from the scene show the vat partially collapsed from the impact of the implosion, with smoke billowing in all directions
Nippon Dynawave Packaging in Longview confirmed that some employees had died when the toxic tank burst at 7.15am Tuesday
Located in Longview just north of the Oregon border, it employs about 1,000 people, according to the Washington State Department of Ecology.
The tank that imploded contained a chemical brew known as 'white liquor,' a corrosive substance that consists mainly of sodium hydroxide and sodium sulfide.
The substance is used to break down wood to make kraft paper, a durable paper used in packaging, shopping bags and other products.
Photographs from the scene show the vat partially collapsed from the impact of the implosion, with smoke billowing in all directions.
A van at the site was also shown partially crushed under a metal pipe, which had a liquid substance spraying from a crack.
Gorsuch, battalion chief with the fire department in Longview, Washington, said first responders had decontaminated patients.
They were taken to hospitals in Longview and Vancouver, Washington.
About 40 firefighters and paramedics had responded, along with a regional hazmat team, Gorsuch said.
The cause of the explosion is unclear. A video from the scene shows ominous white clouds emanating from the facility in the aftermath of the implosion.
Mike Gorsuch, battalion chief with the local fire department, described what he saw as a 'mass casualty scene'
A van at the scene of the implosion was also shown partially crushed under a metal pipe
Washington State Governor Bob Ferguson said the National Guard has been placed on alert.
'My team and I are tracking developments in Longview closely after a major chemical explosion,' he added.
'Responders from our state Department of Ecology have been deployed to the scene.'
I'm deeply saddened to hear that there have been fatalities. My thoughts are with the workers and their families, and with the first responders.
It comes after a tank containing a hazardous chemical was damaged at a Southern California aerospace plant, prompting mass evacuations.
Officials ordered 50,000 residents to temporarily leave their homes, citing the risk of a catastrophic explosion.
The storage tank at GKN Aerospace, containing about 6,000 to 7,000 gallons (23,000 to 26,500 liters) of methyl methacrylate, overheated last week in Garden Grove, a city in Orange County.
Officials have said the tank vented vapors as pressure and temperatures rose, but that monitoring has not detected hazardous chemical levels in the atmosphere.
No injuries have been reported.
Multiple people have been killed and several more are missing after a chemical vat imploded at a paper mill in Washington state. The exterior of the Nippon Dynawave Packaging is shown
While officials said Monday that an overnight inspection confirmed a crack in the tank relieved pressure and cooled the chemical, they said some risk to public safety remained, including a possible fire, spill or small explosion.
Methyl methacrylate is a flammable, colorless liquid used in the production of resins, plastics and plastic dentures and is regulated by the federal government.
It can irritate the lungs, eyes and skin, and in high doses can cause reduced lung function, along with dizziness and memory problems, according to the Environmental Protection Agency.
In prolonged cases, exposure to methyl methacrylate can cause serious respiratory problems or render a person unconscious.
Tests have found that air pollution in the evacuation zone is within normal limits.