Longview: The implosion of a chemical tank at a pulp and paper mill in Washington state Tuesday killed an undisclosed number of people, local authorities and company officials confirmed.

Several people were also injured.

Emergency services described the incident as a “mass casualty scene”, though the exact number of people hurt has not yet been confirmed. Mike Gorsuch, a battalion chief with the Longview Fire Department, said patients suffered chemical burns and inhalation injuries. They were decontaminated at the scene before being transported to hospitals in Longview and Vancouver.

The incident occurred at the Nippon Dynawave Packaging Co facility, a large pulp and paper mill and liquid packaging plant producing materials used in products such as tissues, printing paper, cups, plates and cartons. The site employs around 1,000 workers, according to the Washington State Department of Ecology.

Around 40 firefighters and paramedics attended the scene, supported by a regional hazardous materials team. The emergency call was received at 7:19am local time.

The company has not yet commented on the incident.

In a separate development, thousands of residents in southern California remain under evacuation orders following damage to a chemical storage tank at an aerospace facility.