WHITING, Ind. (AP): Workers at BP's sprawling northwestern Indiana oil refinery remain on the job even as many U.S. refinery workers are taking part in a walkout.

The United Steelworkers Local 7-1 had put BP on notice that workers at its Whiting refinery about 20 miles southeast of downtown Chicago would go on strike at 11:59 p.m. Sunday.

But a strike was averted Sunday when the two sides reached a rolling 24-hour contract extension.

BP spokesman Scott Dean says the extension demonstrates “both sides continue to negotiate diligently and in good faith.''

Contract talks are underway nationally, and the United Steelworkers union called Sunday for work stoppages at nine refineries and plants in Texas, California, Kentucky and Washington state.

Workers went on strike after their shifts ended.