Union workers were on strike for a second day on Monday at nine U.S. refineries and chemical plants as they sought a new national contract with oil companies covering laborers at 63 plants. The walkouts were the first in support of a nationwide pact since 1980 and targeted plants with a combined 10 percent of U.S. refining capacity. One of the plants, Tesoro Corp’s ( TSO.N ) 166,000-barrel-per-day Martinez, California, refinery, was being shut because it was in the midst of planned maintenance work. The other refineries appeared set to continue running normally as operators initiated contingency plans, calling on trained managers as replacement workers. U.S. gasoline and diesel fuel prices rose on Monday on concerns over supply, as well as a bounce in crude. Talks broke down against a backdrop of plunging crude prices, down nearly 60 percent since June, prompting oil companies to cut […]