(Adds details, background on negotiations)
HOUSTON, Nov 19 (Reuters) - United Steelworkers union locals representing 30,000 U.S. oil refinery and chemical plant workers ratified terms for contract proposals in negotiations that are to start in January, the union said on Monday.
The proposals, which include an 8 percent pay increase for each year of a three-year agreement, were developed by the USW's National Oil Bargaining Policy conference in San Diego in late September.
At least 75 percent of the USW locals representing 220 plants were required to ratify the proposals, which will be presented to negotiators from Shell Oil Co., the U.S. arm of Royal Dutch Shell Plc, which will represent refinery and chemical plant owners.
"We look forward to a productive set of talks with the USW and will bargain in good faith to reach a mutually-acceptable agreement," Shell spokesman Ray Fisher said on Monday.
USW spokeswoman Lynne Hancock said the union also looks forward to the negotiations. "We are hopeful of reaching an agreement that enables both sides to prosper," Hancock said.
The current contract expires on Feb. 1. It was agreed to after a 2015 strike affecting 7,000 workers at 12 refineries and three chemical plants that lasted nearly six weeks, the industry's largest work stoppage in 35 years. (Reporting by Erwin Seba; Editing by Dan Grebler)