LONGVIEW, Washington (From news reports) -- A chemical tank ruptured at a facility in Washington state, resulting in multiple critical injuries and fatalities, authorities said.

The "hazardous materials incident" was reported Tuesday morning, May 26, at the Nippon Dynawave Packaging in Longview, fire authorities said.

A tank containing white liquor ruptured at approximately 7:15 a.m., according to a joint statement from local authorities and Nippon Dynawave Packaging.

Authorities initially referred to the incident as a chemical explosion and then an implosion, before referring to it as a rupture.

Multiple people suffered injuries, including chemical burns, and were transported by ambulance to area hospitals, the fire department said. The extent of their injuries is unclear, it said.

The number of patients in the incident is "double digits," Rick Graves, the spokesperson for Portland Fire and Rescue in Oregon said. Patients with traumatic injuries are being treated at nearby medical facilities, while patients experiencing burns and exposure are being sent to other hospitals around the area, including in Portland, which are considered burn centers, he said.

PeaceHealth St. John Medical Center in Longview said it received nine patients from the incident -- including one deceased. Six are in fair condition, and two other patients have been transferred, it said.

Information on those killed and injured in the incident is being held pending next-of-kin notifications, authorities said.

There is no immediate threat to the public, authorities said.

"The scene remains in the recovery phase as emergency responders continue operations," the joint statement said. "Responding agencies continue coordinating closely with facility personnel and partner agencies as the investigation and recovery efforts continue."

Residents were urged to avoid the area amid the active emergency response.

The Nippon facility is located on the Washington-Oregon border near the Columbia River. It is a kraft pulp and paper mill and liquid packaging plant, according to the Washington Department of Ecology.