Rescue crews returned Wednesday to the wreckage of a Washington state paper mill where a massive chemical tank imploded, as officials acknowledged there is “no hope” of finding the remaining missing workers alive.

Authorities now fear 11 people may have died in the disaster at the Nippon Dynawave Packaging Co. plant in Longview after a second injured victim succumbed to injuries, according to officials.

Nine workers remain unaccounted for following Tuesday’s catastrophic rupture of a tank containing more than 500,000 gallons of “white liquor,” a corrosive chemical solution used in paper production.

Yellow caution tape reading "CAUTION: SHERIFF LINE - DO NOT CROSS" in front of the Nippon Dynawave Packaging facility.
Yellow caution tape in front of the Nippon Dynawave Packaging facility.Getty Images

A spill response team vehicle is parked in front of a packaging facility following a chemical implosion.
A spill response team vehicle is parked in front of a packaging facility following a chemical implosion.Getty Images

An aerial view shows a ruptured chemical tank, collapsed on its side next to a building, with debris and liquid spilled on the ground.
A drone view of a chemical tank after its rupture.REUTERS
“We do not know where all nine are,” Cowlitz County fire chief Scott Goldstein said Wednesday as emergency teams resumed recovery operations at the devastated site.

Search efforts had briefly been halted because officials worried the damaged tank could collapse again.

Nippon Dynawave Packaging Company during an explosion.
Authorities now fear 11 people may have died in the disaster.Cowlitz County News
Crews later determined the structure was stable enough to continue after discovering it held less liquid than originally believed.

Officials warned the operation would move slowly as responders comb through the dangerous scene.

The blast also left eight others injured, including a firefighter who was treated and released from a hospital.

Damage at Nippon Dynawave Packaging Company with a white Ford pickup truck under a large green pipe.
If confirmed, the disaster would rank among the deadliest workplace accidents in the US in recent years.Cowlitz County News

A Fire and Rescue vehicle parked outside the Nippon Dynawave Packaging pulp and paper mill after a chemical tank rupture.
Some chemical contamination did reach the Columbia River and additional monitoring remains underway.REUTERS

Gilbert Bernal (left), another man, and a woman posing outdoors.
Gilbert Bernal is one of several people injured, missing, or killed after the implosion.GoFundMe
The accident unfolded at the Longview facility near the Washington-Oregon border, in a city of roughly 40,000 residents with deep roots in the timber and paper industries along the Columbia River.

Authorities said testing so far shows the rupture has not threatened Longview’s drinking water or air quality, though some chemical contamination did reach the Columbia River and additional monitoring remains underway.

Spill Response Team truck of the Washington State Department of Ecology.
Spill Response Team truck of the Washington State Department of Ecology.Getty Images
If confirmed, the disaster would rank among the deadliest workplace accidents in the US in recent years.

Officials compared the potential toll to a deadly Tennessee explosives plant blast last fall that killed 16 people, the 2013 fertilizer plant explosion in Texas that left 14 dead, and the 2010 Deepwater Horizon oil rig catastrophe that claimed 11 lives.

The Washington tragedy came just days after another major West Coast chemical emergency.

In Southern California, a failed cooling system is believed to have sparked a hazardous leak at a Orange County aerospace facility, prompting the evacuation of about 50,000 residents from Thursday through Tuesday over fears of an explosion.