By Erwin Seba
HOUSTON (Reuters) - Talks to end the largest U.S. refinery strike in 35 years are not expected to resume this week, sources familiar with the negotiations said on Monday after the number of plants hit by walkouts increased over the weekend.
Face-to-face meetings between the United Steelworkers union (USW) and lead refinery owner representative Shell Oil Co, the U.S. arm of Royal Dutch Shell Plc, might remain on hold until the second week of March, the sources said.
The halt in talks comes after the USW pulled workers from three Motiva Enterprises LLC [MOTIV.UL] refineries in Louisiana and Texas co-owned by Shell after oil companies balked at a possible settlement.
Over the weekend, sources said negotiations might resume by the middle of this week.
About 6,550 workers are walking picket lines at 15 plants, including 12 refineries that account for one-fifth of U.S. refining capacity. Refiners are using trained replacement workers, primarily managers and engineers, to keep plants running close to normal.
In a text message on Monday night sent to union members and the news media, the USW called on Shell to return to the negotiating table.
A spokesman said Shell looks forward to resuming negotiations.
More information might come from a news conference USW International President Leo Gerard has scheduled for Tuesday morning in Atlanta.
In a letter to employees, Shell said the major sticking point in the talks was the USW's push to shift daily maintenance work from non-union contractors to union members.
The company said it offered a 6.5 percent increase in pay to the USW over the three years of the agreement.
In a letter on Monday night, Tesoro Corp Executive Vice President Keith Casey urged striking workers to return to work at company refineries on the West Coast.
"I can confirm we have had folks make this decision and rejoin us at all of our refineries," Casey said. "The same is occurring across the industry."
Casey also said Tesoro is preparing to restart its 166,000 barrel-per-day (bpd) refinery in Martinez, California, which has been shut since Feb. 6 for a planned multi-unit overhaul.
Workers are also striking at the Shell refinery and chemical plant in Deer Park, Texas, and at plants in California, Indiana, Kentucky, Ohio, Texas and Washington owned by BP Plc, Lyondell Basell NV, Marathon Petroleum Corp and Tesoro.
(Reporting by Erwin Seba; Editing by Andre Grenon and Lisa Shumaker)