Biodiesel also may reduce health risks associated with petroleum diesel.

Biodiesel's physical properties are similar to those of petroleum diesel, but the fuel significantly reduces greenhouse gas emissions and toxic air pollutants.

Until recently, 100 percent biodiesel cost 50 cents to $1 a gallon more than petroleum diesel or home heating oil.

The used cooking oil is chemically treated to create a biodiesel similar to petroleum diesel.

Blending B100 with petroleum diesel may be accomplished by:

Nothing; biodiesel is identical to petroleum diesel.

In many engines, it can be used in pure form or as a blend with petroleum diesel.

Biodiesel can be used in its pure form (B100) or blended with petroleum diesel.

Biodiesel prices vary across the country and tend to be slightly higher than those for petroleum diesel.

At the wholesale level, petroleum diesel varies from 60 cents to $1.20 in California.