TOMAHAWK, Wis. — A storage tank explosion at a paper mill Tuesday killed three maintenance employees and injured a fourth, according to the company, Packaging Corporation of America.
The company, based in Lake Forest, Ill., said in a statement that the three were performing maintenance work atop a recycled fiber storage tank when it exploded about 1:30 p.m.
A fourth employee was standing on a platform at a lower level of the tank, the company said.
Company spokesman Ron Zimmerman said up to 10 people were working in the area when the explosion happened in what he described as "a storage tank for pulp." No fire resulted from the explosion, he said.
The cause of the explosion was not known and is under investigation, the company said.
Identities of the victims were not being released Tuesday night, Zimmerman said. He declined to give ages or other information about them.
Capt. Mike Drury, from the nearby Merrill Fire Department, said his rescue crew was called to help free the employees about 1:40 p.m. but was called off before it arrived. Emergency workers on the scene used a crane to rescue them, he said.
"There was an explosion and a couple of employees were trapped for a short period of time," Drury said.
The mill is part of a large complex spread over several blocks, Drury said.
The main part of the mill remained in operation Tuesday afternoon.
Workers walked out with somber faces, refusing to comment.
One man was met by a woman in a car, and they embraced and hugged for nearly a minute. The man talked with her for several minutes and then went back into the administrative office, telling a reporter he couldn't comment.
One worker said the explosion happened in a rear area of the property.
He said employees had been told not to discuss details of the explosion with reporters, referring questions to Zimmerman.
Carol Levanetz rushed to the plant from Rhinelander after hearing about the explosion.
Her son, Bryan Papineau, was OK, she said after checking at the mill's main office. She learned the explosion happened two hours before his work shift started.
"Now I just have to get my stomach settled. I'm waiting for him to call," she said. "I am just so sad for those other people."
The Lincoln County Sheriff's Department did not immediately return a telephone message Tuesday.
Packaging Corp. of America, which makes containerboard and corrugated packaging products, operates four paper mills and 67 corrugated product plans in 26 states. According to the company's Web site, it employs 8,350 people nationwide and posted sales of $2.3 billion last year.
The Tomahawk mill has three semi-chemical corrugating machines and produces more than 572 million tons annually, the company said. The tank that exploded was used to store a product used to make paper at the mill.