* Rallies held at 15 plants and Chicago headquarters
* Union-company talks continue
* ArcelorMittal stock closes down 1.8 percent on NYSE
By Steve James
Sept 5 (Reuters) - Unionized steelworkers staged rallies outside all of ArcelorMittal's plants in the United States on Wednesday, accusing the steelmaker of dragging its feet in talks over a new labor contract.
Tony Montana, a spokesman for the United Steelworkers union (USW) said the "corporate-wide mobilizations" took place at 15 ArcelorMittal plants, as well as at the company's U.S. headquarters in Chicago.
"Our members held spirited rallies to show their solidarity with our bargaining committee as we continue negotiating for a fair contract at ArcelorMittal," Montana told Reuters in a telephone interview.
He described the actions as "a variety of activities," including informational picketing, chanting and marching.
The Luxembourg-based company, the world's largest steelmaker, took precautionary measures at its plants last week in case of a strike. The union said it has not taken the strike option off the table.
Montana said negotiations were continuing with ArcelorMittal after the union separately reached a tentative agreement on a new contract with U.S. Steel Corp on Sunday for more than 16,000 workers.
The USW's previous contracts with U.S. Steel and ArcelorMittal both expired at midnight on Saturday.
"With U.S. Steel reaching a tentative agreement over the weekend, why does ArcelorMittal continue to drag its feet?" David McCall, chairman of the USW negotiating committee, said in a letter to about 10,000 USW members at the company's plants in Indiana, Ohio and other U.S. states.
The union said the main sticking points in the contract talks were over funding for retiree health-care premiums and for pension benefits.
William Steers, a spokesman for ArcelorMittal USA in Chicago, did not comment on the USW action.
"Negotiations continue between ArcelorMittal and the United Steelworkers. We remain optimistic about reaching a fair and equitable contract with the USW," he said in an e-mail to Reuters.
The possibility of a work stoppage comes at a difficult time for the steel industry, which is suffering from weak demand and low prices. U.S. steelmakers have cut capacity to manage supply, but demand has still not returned to pre-recession levels.
Last month, ArcelorMittal said tough market conditions would continue into the second half of the year, particularly in Europe, where it lowered its consumption forecast due to the severity of the slowdown.
ArcelorMittal stock closed down 1.8 percent at $14.38 on the New York Stock Exchange.