More than 400 striking hourly workers represented by the United Steelworkers union (USW) at Lyondell Basell Industries' Houston refinery are scheduled to vote on the company's last, best and final offer on Monday and Tuesday, a local union official said on Sunday.

"We were presented with a last, best and final offer yesterday evening," said Kent Farr, an official of USW local 13-227.

A Lyondell spokesman confirmed the company sent the offer across the negotiating table on Saturday night.

Companies usually make a last, best and final offer in an attempt to bring negotiations to a close. If the offer is rejected, the company can declare an impasse and impose rules that take the place of a contract. Negotiations can continue while such rules are in place.

USW Local 13-227's executive committee recommended on Sunday that the union's membership reject the offer.

Talks between the union and Lyondell have been focused on the company's proposal to curtail long-standing rules on overtime pay that allow a worker to receive several wage premiums when working extensive overtime hours.

Hourly workers went on strike at the 263,776 barrel-per-day (bpd) Lyondell refinery on Feb. 1, as part of the largest U.S. refinery workers' strike in 35 years.

A total of 6,550 workers walked off their jobs at 15 plants including 12 refineries that account for one-fifth of national refining capacity. A national settlement was reached on March 12.

As at Lyondell's Houston refinery, ongoing disagreements over local issues have kept strikes going at Marathon Petroleum Corp's Galveston Bay Refinery and South Houston Green Power Plant in Texas City, Texas; BP Plc's Whiting, Indiana, refinery and the BP and Husky Energy joint-venture refinery in Toledo, Ohio.