LONGVIEW, Washington (From news reports) -- The remains of all missing victims in a Washington state paper mill implosion have been recovered, officials announced Saturday.

"Today, on day five of this incident, I can share that we have recovered the ninth and final missing employee of this incident," Longview Fire Chief Brad Hannig said in a Saturday news conference.

Recovery efforts had been ongoing since Tuesday's chemical tank implosion and rupture at the Nippon Dynawave plant in Longview. Two victims were transported to hospitals and later died, bringing the death toll to 11.

The deceased were identified as Gilberto Bernal, 52; Tyler Covington, 29; Brad Covington, 27; Robert Wilson, 48; Dale Miller, 54; Jared Ammons, 35; Braydon Finkas, 38; Clinton Duran, 26; John Forsberg, 51; Norman Barlow, 58; and Dillon Miller.

The tank was designed to hold 900,000 gallons of a hazardous chemical known as white liquor, a chemical brew that contains sodium hydroxide, sodium sulfide and disodium carbonate and is used in the paper-pulping process, officials have said.

The implosion happened at 7:15 a.m. as workers were on a shift change, according to officials.

Kurt Stich, deputy chief with Cowlitz 2 Fire and Rescue, said the recovery process was "methodical and incredibly difficult for everyone that's been involved." That effort included moving heavy items indoors and conducting drone flyovers "to make sure that we were not missing anything."

Officials had been diluting high-pH water in ditches that were contaminated with chemicals that spilled. Brooks Stanfield, the federal on-scene coordinator for the Environmental Protection Agency, said Friday that there had been improvement in the pH levels in the ditch system.

The ditch sits atop an aquifer and a well field that supplies Longview's drinking water, he said. But officials stressed that contaminated water was diverted away from the wellhead area and that that Longview's water is safe.

The investigation into the cause of the implosion is ongoing.