The death toll from a chemical tank rupture in the US state of Washington climbed to 11 as crews ?recovered the bodies of all nine missing people, authorities said on Saturday.

Two fatalities had been confirmed after the tank containing “white liquor” – a chemical solution of sodium hydroxide and sodium sulfide used in making paper pulp – imploded at a Nippon Dynawave Packaging facility on Tuesday.

The search for the missing carried on through the week as recovery crews worked through debris in indoor areas and flew drones over the perimeter of the site, said Cowlitz 2 Fire & Rescue’s deputy ?chief, Kurt Stitch.

The ruptured tank contained about 900,000 gallons (3.4 million liters) of white liquor, and tests confirmed that contamination entered the nearby Columbia River, officials have said, although no “negative health impacts” had been detected on air quality or the city of Longview’s drinking water.

Nippon Paper Industries, Japan’s second-biggest paper manufacturer by sales, acquired the Longview plant from Seattle-based timber company Weyerhaeuser for $225 million and established the wholly owned subsidiary Nippon Dynawave Packaging in 2016.