Fuelmakers in California could face more headwinds next year as new legislation takes effect and refining margins remain weak, the U.S. Energy Information Administration (EIA) said on Monday. California, the most populous U.S. state, consistently faces some of the nation's highest average gasoline prices, leading to an often tense relationship between the state and oil companies. However, imported fuels are likely to become a more important source of supply for California as refineries in the state struggle with profitability, the EIA said in an analysis on Monday.