U.S. oil refiners could cut output by as much as 25 percent and the nation's reliance on imported refined products could double in the next twenty years if climate legislation now being considered in the U.S. House of Representatives becomes law, the American Petroleum Institute said on Monday. Under the “cap-and-trade” bill narrowly passed by the House in June, refining output could fall by as much as 4.4 million barrels per day by 2030 to 12 million barrels per day, the Institute said, quoting a study it commissioned by EnSys Energy. Imports could account for up to 19.4 percent of consumption by 2030 under the climate law, the study said, up from a projected 9.6 percent if the law were not in place. Investment in U.S. refineries could fall by as much as $90 billion by 2030, a decline of 88 percent. The House bill aims to curb greenhouse gas emissions by 17 percent from 2005 levels by 2020, and requires polluters to get permits for the carbon dioxide they spew into the atmosphere. Under the bill, refiners are responsible not only for the 4 percent of emissions released from refineries when processing crude oil, but also the gases emitted from use of fuels produced such as gasoline and heating oil. In total, refiners would be accountable for more than 40 percent of emissions, forcing them to purchase the majority of their permits. Analysts have said the House bill could cripple refiners, particularly small, independent facilities already reeling from weak demand and improving fuel efficiency. The Senate will work on its version of the bill in September.