One person is confirmed dead and nine others are unaccounted for after a Washington state chemical implosion that has proven to be even larger than previously reported.

A vat containing around 900,000 gallons of toxic chemicals exploded at a paper mill in the town of Longview around 7 a.m. Tuesday, sending eight workers and one firefighter to the hospital — some with horrific burns, officials said.

“Officials can also confirm there are 9 employees who remain unaccounted for,” the city of Longview said in a Tuesday evening update.

The vat — on a paper mill operated by Nippon Dynawave Packaging — contained “white liquor,” a chemical combination of sodium hydroxide, sodium sulfide, and disodium carbonate.

Officials initially reported the vat held 80,000 gallons of the deadly chemical, but officials later confirmed it actually held more than ten times that amount.

Around 90,000 gallons remain inside the tank, which remains unstable — hindering search and rescue operations for the missing workers, officials said in a Tuesday evening press conference.

“The site will continue to be monitored overnight, but recovery efforts will not resume until tomorrow due to ongoing safety concerns,” city officials said.

There is no immediate threat to the public, officials said. Nippon Dynawave Packaging Facility is a paper mill with 550 employees that makes “around 280,000 tons of bleached liquid packaging paperboard, and wetlap and slush pulp” each year, according to the Washington State Department of Ecology.

The company says its products “are converted into 8 billion single-serve containers per year.”

Gov. Gavin Newsom declared a state of emergency in the county as a chemical tank containing thousands of gallons of methyl methacrylate uncontrollably heated up, before officials were able to halt the temperature climb.

A Nippon Dynawave Packaging Facility employee told The Post that they had “no information” at that time to provide when contacted for comment.