Jan 31 (Reuters) - United Steelworkers members at BP's

440,000-barrel-per-day refinery in Whiting, Indiana,

rejected the company's offer to extend their contract ‌by 28 days

at the largest refinery in the U.S. Midwest, ​the company said in

a statement on Saturday.

United ‍Steelworkers Local 7-1, which represents around ⁠800

workers at ⁠Whiting, said on Friday in a statement to members ‌on

its website that the ​two sides remain apart, but workers should

report to work as scheduled to ensure ⁠the facility's safe

operation.

"While ‍there is ​no intent to have a work stoppage, we need

to be prepared," the union said. "Our ‍plans for strike or

lockout have been initiated. We ask that you not be alarmed by

this activity. We will continue to bargain with the goal of

reaching an agreement that ​is ‍mutually beneficial by February

1st."

The union has previously said BP proposed cutting more than 200

union ​jobs in operations, maintenance and environmental safety.

It said in its statement on Friday there were differences

over issues such as seniority, layoffs and wages.

The collective bargaining agreement expires on Saturday.

The Whiting refinery produces ​transportation fuels including

gasoline, diesel fuel and jet fuel.

BP and the union did not immediately respond to requests for

further comment.