El Nino and the warm winter weather are being blamed for the weak demand for distillate fuel oil in the United States, but the slump in oil production is probably having a bigger impact. The oil industry was the fastest-growing customer for middle distillates like diesel between 2009 and 2014, according to the U.S. Energy Information Administration (EIA). The oil industry itself accounted for 20 percent of all the increase in diesel consumption during the five-year drilling boom. Businesses engaged in oil drilling, pipelines and refining consumed 2.1 billion gallons of diesel in 2014, the most recent data available, up from just 760 million gallons in 2009. By 2014, oil producers accounted for 3.5 percent of all distillate fuel oil sales in the United States, up from 1.4 percent in 2009. Drilling rigs and the massive pumps employed for hydraulic fracturing all use high-horsepower engines which run 24 hours per day and consume prodigious quantities of fuel. The heavy trucks used to haul drill pipe, frac sand and water to well sites, and carry away crude before the well is hooked up to gathering pipelines, are all diesel powered. And since many oil fields are in remote rural areas with little or no electricity supply from the main power grid, most of the electricity used for heating and lighting also comes from diesel generators.