A tank containing a substance known as white liquor burst at the Nippon Dynawave Packaging Company in Longview, an hour north of Portland on the Washington-Oregon border, a statement said.
"Preliminary information indicates the rupture resulted in multiple critical injuries," said the statement, issued jointly by the company and Longview Fire Department.
"Officials can also confirm fatalities related to the incident."
The statement gave no numbers on the people killed or injured, but said there was no threat to the public.
The Seattle Times, citing firefighting officials, said 10 people had been hurt: nine company employees and one firefighter.
