United States policy in regard to biofuels, such as ethanol fuel and biodiesel, began in the early 1990s as the government began looking more intensely at biofuels as a way to reduce dependence on foreign oil and increase the nation's overall sustainability. Since then, biofuel policies have been refined, focused on getting the most efficient fuels commercially available, creating fuels that can compete with petroleum-based fuels, and ensuring that the agricultural industry can support and sustain the use of biofuels.