Cold Weather Causing More Biodiesel Problems in Minn.

The Bloomington, Minn., School District closed all of its schools Thursday because biodiesel fuel gelled and clogged in the district's buses, the Minneapolis-St. Paul Star-Tribune reported.

State law requires that all diesel sold in Minnesota contain 2% biodiesel, which gels at temperatures below 10 degrees, the Star-Tribune said. Some of the district's buses did not start Thursday morning, while some experienced problems.

The Bloomington School District tried to get a waiver to run its buses on pure diesel Thursday, but did not get it, the Star-Tribune said.

To combat to gelling problem, some school districts keep their buses in temperature-controlled garages. Some bus contractors idle their buses throughout the night, the Star-Tribune said.

In the past several years, truckers subjected to Minnesota's mandate have reported problems with biodiesel gelling in cold weather.