Conventional gasoline and diesel are produced by distilling and refining crude oil in large, centralized refineries. From there, these finished fuels are transported in bulk via pipelines, tanker ships, railcars, or trucks to regional storage terminals. At these terminals, fuels are held in large tanks where additives may be blended in to meet specific performance and regulatory standards. Finally, tanker trucks deliver the gasoline and diesel from the terminals to underground storage tanks at individual retail filling stations, completing a complex and highly integrated global supply chain.