The petroleum refining industry continues to be a strong contributor to the U.S. economy. Shipments were variable over the last decade but overall have increased about 4% annually. For U.S. refiners the 1990s were characterized by low product margins and low profitability. Reasons include the cost of regulation, variable crude prices, changing crude quality, and low marketing and transport margins. Petroleum products are also heavily taxed — taxes on gasoline sales, for example, can represent as much as 20% of market price.

U.S. refiners rely on both domestic and foreign producers for crude oil, as well as some unfinished feedstocks and refined products. Historical trends show that imports of crude oil have been rising steadily over the last 10 years and reached a record high of 10 million barrels per day in 1997. [DOE 1998]