Before 2004, diesel typically cost less than gas, according to the federal Energy Information Agency. Then, the Environmental Protection Agency started requiring operators to use ultra low sulfur diesel. So-called ULSD is processed from crude oil to have a sulfur content of no more than 15 parts per million, compared to the previous standard of 500 ppm.

The low-sulfur diesel burns cleaner and is more expensive to make, according to the EIA.

In addition, overall demand has spiked, putting pressure on diesel producers. From 2000 to 2006, domestic diesel sales jumped about 21 percent. Oil refineries in the United States have been operating at more than 90 percent capacity for about 10 years, according to the EIA. Since a 42-gallon barrel of crude oil produces only about 8 gallons of diesel, supplies have been squeezed.

Finally, taxes on diesel sales have increased and now stand at about 24 cents per gallon.

All of these costs are being passed on to consumers. In the Midwest, the average cost of a gallon of diesel fuel was $4.10 as of May 5. That’s a 50 percent increase from one year ago.

Staff writer Ray Weikal can be reached at

389-6637 or rayweikal@npgco.com.

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