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Biodiesel blends above 5 percent must be labeled

I was wondering what the rules are for labeling the total content of biodiesel in the diesel fuel being pumped at a given station. I am told that most diesel being sold today contains biodiesel. I am also told that the vendor does not have to disclose if or how much biodiesel is being added.

— Jeff, White City 

Putting large concentrations of a non-petroleum based fuel in a diesel engine that wasn't engineered for it can indeed cause problems, particularly for fuel filters and rubber hoses in vehicles made before 1993. Thankfully, your station isn't "fueling around."

To straighten out what you may have heard, a vendor does have to disclose biodiesel content for any diesel fuel blend greater than five percent — the Oregon Department of Agriculture's Weights and Measures division says so. The division oversees how fuels are sold in our state, and oversees fueling station regulations including the signs at the gas station that advertise fuel prices. In the case of your query, the division ensures that biodiesel fuel blends are clearly labeled at the pump.

According to information about biodiesel blends on the U.S. Department of Energy site, low-level blends up to five percent biodiesel are approved for use with all diesel engines by the American Society for Testing and Materials, which develops specifications for conventional diesel fuel. That unlabeled five percent grade falls within all manufacturer warranties. Blends are labeled differently if there is between six and 20 percent biodiesel, or if the biodiesel content is greater than 20 percent.

Grades greater than B20 are less common, according to the Department of Energy, but pure biodiesel has slightly different characteristics, including a lower energy density and an ability to gel in cold temperatures.

Send questions to “Since You Asked,” Mail Tribune Newsroom, P.O. Box 1108, Medford, OR 97501; by fax to 541-776-4376; or by email to youasked@mailtribune.com. We’re sorry, but the volume of questions received prevents us from answering all of them.