HOUSTON (Reuters) - Managers at BP Plc (>> BP plc) and Husky Energy's (>> Husky Energy Inc.) joint-venture Toledo, Ohio, refinery said they reached agreement on a tentative contract on Saturday with union workers, a step towards ending a strike that has lasted nearly four months.

A spokeswoman for the United Steelworkers union (USW), which represents the striking workers, did not have information about the agreement on Saturday afternoon.

USW Local 1-346 had offered on Wednesday night to end the strike and continue bargaining with the company while the more than 300 workers returned to their jobs.

Temporary replacement workers have kept the 135,000 barrel per day (bpd) Toledo refinery in operation since the strike began on Feb. 8.

"The USW will begin their ratification process and we expect a vote sometime this week," said Jeff Steigauf, the Toledo refinery's human resources manager in a statement.

"Concurrently, representatives of the company and union will be negotiating the terms of the return to work agreement to ensure the safe and orderly transition of the hourly workforce back into the refinery," Steigauf said.

Returning the union workers to their jobs has taken up to three weeks at 13 other chemical plants and refineries where strikes have taken place since early February.

No terms of the tentative pact were disclosed by the refinery on Saturday, but the agreement should be for four years and include a pay raise of 2.5 percent in the first year, 3 percent in the second and third year and 3.5 percent in the fourth year.

The pay raises were part of a national agreement reached in March between the USW and U.S. refinery owners to end a the largest strike by refinery and chemical plant workers in 35 years. Toledo refinery workers continued their walkout as union and company negotiators wrangled over local issues.

The Toledo refinery was one of 12 U.S. refineries, accounting for one-fifth of national refining capacity, where workers were called to strike by the USW's international leadership. Workers also went on strike at three chemical plants.

Workers at one other refinery, Marathon Petroleum Corp's (>> Marathon Petroleum Corp) Galveston Bay Refinery in Texas City, Texas, remain on strike over local issues.

(Reporting by Erwin Seba; Editing by David Gregorio)

Stocks treated in this article : Husky Energy Inc., Marathon Petroleum Corp, BP plc