Workers hold picket signs as they strike outside the Tesoro refinery in Carson, California March 4, 2015. Labor leaders and oil company representatives will resume face-to-face talks on Monday in Houston in a bid to agree on a new contract that would end the biggest U.S. refinery strike in 35 years, the United Steelworkers union said on Wednesday. The strike, now in its second month after starting Feb. 1, has dragged on as both sides fail to reach agreements over wage increases and how to curb worker fatigue, which is tied to accidents. About 6,550 workers are on strike at 15 plants, including 12 refineries that account for a fifth of U.S. capacity. REUTERS/Lucy Nicholson (UNITED STATES - Tags: BUSINESS COMMODITIES ENERGY CIVIL UNREST)