JEFFERSON CITY, Mo. — Biodiesel took another step towards more widespread usage as standards-setting unit ASTM International published recently approved standards for stronger blends of the fuel.

In June, ASTM International’s technical committee passed the new specifications, which include new standards blends containing between 6 and 20 percent biomass (B6 to B20), as well as revisions that would allow blends up to 5 percent biomass (B5) in regular diesel, pure biodiesel and biodiesel for home heating. The publication finalizes this approval.

Three major school bus engine manufacturers, Caterpillar, Cummins and Navistar have already approved some of their engines for blends up to B20 and B30. As of June, Detroit Diesel, Mercedes Benz and Volvo had yet to approve biodiesel blends beyond B5.

According to Jenna Higgins Rose, a spokesman for the National Biodiesel Board, "All other major U.S. automakers and engine manufacturers accept the use of at least B5, and most are rapidly advancing toward full B20 support now that the new ASTM standards for B20 have been approved by ASTM International."

The Engine Manufacturer’s Association, which participated in the standard development, said individual companies will have to look at the standards to see if they will approve their engines for higher blends of diesel but suggested the standards might encourage further development.

"These standards, when fully enforced, in conjunction with the Federal Trade Commission pump labeling requirements will provide engine manufacturers and their customers confidence that the fuels will perform as expected," said Roger Gault, EMA technical director.