SAN DIEGO (Reuters) - Union officials representing 30,000 workers at U.S. oil refineries and chemical plants on Wednesday said they will pursue sizable wage increases and a 3-year contract in coming negotiations.

FILE PHOTO: James Prokupek (L), an engineering department process design manager for the Valero St. Charles Oil Refiner, is seen in silhouette during a tour of the refinery in Norco, Louisiana, August 15, 2008. REUTERS/Shannon Stapleton/File Photo

Contract talks, which begin in January, come as U.S. refiners are enjoying strong profits, near-full utilization rates and record product exports. In the June quarter, the margin on turning crude to gasoline, diesel and other products was the highest since 2015.

The United Steelworkers union (USW) wants a wage increase comparable to the 6 percent per year increase it originally sought during 2015 talks, Kim Nibarger, chairman of the USW’s national oil bargaining program, said in an interview following a three-day union meeting in San Diego.

In 2015, USW members went on a six-week strike at 12 U.S. refineries and three chemical plants. In the end, they accepted a four-year contract that provided members between 2.5 percent to 3.5 percent annual increases each year and changes to working conditions.

Nibarger declined to provide specifics of the proposals that union officials will bring to their members in coming weeks. Local union members will have 45 days to vote on the proposals reached on Wednesday. If 75 percent of locals agree, the wage increase will be presented to companies in January.

“They are in the range of the proposals made in 2015,” he said. “I think it is an aggressive proposal, but not unreasonable given the dedication of members to keep their facilities operating at top notch.”

Shell Oil Co, the U.S. arm of Royal Dutch Shell Plc RDSa.AS was once again named lead negotiator on behalf of companies that own U.S. refineries, including Marathon Petroleum Corp MPC.N BP Plc BP.L, Exxon Mobil Corp XOM.N, Valero Energy Corp VLO.N, and smaller refiners such as HollyFrontier Corp HFC.N and Delek US Holdings Inc DK.N.

Shell declined immediate comment on Wednesday.

“Our goal is a mutually beneficial agreement for our members and the companies they work for,” said Nibarger.

The USW also wants improvements in a standard meant to reduce fatigue among its workers. It sought a similar change in 2015, he said.

In 2015, the national strike lasted six weeks and some local strikes continued for months with workers at the Marathon Galveston Bay Refinery in Texas not returning to work until July.

The current USW contract runs out on Feb. 1.