An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Verified Technologies for SmartWay and Clean Diesel

Various Technology—Biodiesel (1-100%)

Biodiesel: Diesel fuel oil modified with 0 to 100% biologically derived oils. The use of biodiesel fuel is one recognized retrofit technology used to reduce diesel engine emissions. Emission reduction information is provided below.

Technology specifications

Engine Model/Application

Highway, heavy duty, 2 & 4 cycle

Reduction in particulate matter (PM) 0-47%
Reduction in nitrogen oxide (NOx) 0-(-10)%
Reduction in hydrocarbons (HC) 0-67%
Reduction in carbon monoxide (CO) 0-47%


  • Reductions for all pollutants must be calculated for a particular biodiesel fuel. Download this  biodiesel reduction spreadsheet (XLS)(2 pp, 23 K, May 2007)  Free Viewers calculation file to use to determine reductions.
  • A negative value in the table above indicates an increase in that pollutant.
  • There are no data on biodiesel effects on engine durability, materials compatibility, fuel storage stability, lubricity, biodiesel production feedstocks or costs, cold flow properties, cost, renewability/full fuel lifecycle emissions.
  • There is a slight fuel economy penalty with biodiesel use. An approximate fuel penalty calculation can be made with calculation worksheets above.
  • Biodiesel fuel is composed of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats meeting the requirements of American Society of Testing and Materials (ASTM) D 6751.
  • A biodiesel blend is a mix of biodiesel fuel meeting ASTM D 6751 with petroleum-based diesel fuel, and designated BXX, where XX represents the volume percentage of biodiesel fuel in the mix.
  • EPA does not endorse the use of any particular company's product.