In an announcement, the union said 13 locals representing about 15,000 employees all approved the authorization. The union said it has so far been frustrated by the company's proposals. 

"ArcelorMittal can easily afford to negotiate fair labor agreements with us, but the company has instead insisted on concessions that would more than wipe out any pay increases in its proposal," said United Steelworkers District 1 director David McCall. "These are jobs worth fighting for, and we intend to keep it that way."

The current labor agreement between ArcelorMittal and the Steelworkers expired 1 September, but the union is continuing to work under a contract extension. It remains at loggerheads with the company on pay and health insurance, among other things.  

In a statement, ArcelorMittal said it is important to note that the strike authorization is not a declaration of a strike and that talks are continuing. 

“We continue to work diligently to reach a mutually agreeable conclusion. Further, our plants continue to operate in a safe and orderly fashion,” the company said. 

Steelworkers are also trying to work out a new contract with United States Steel Corporation. Union employees already have given union leaders permission to call a strike.