ST. PAUL, Minn. The biodiesel fuel program in Minnesota got temporarily plugged-up this month after state officials received complaints about clogged fuel filters. The state biodiesel law was suspended for three weeks.

In late September, Minnesota adopted the law mandating that diesel fuel be blended with 2 percent biodiesel. (See Jan. 1 Bus & Motorcoach News.) Due to complaints last month, the Weights and Measures Division of the Minnesota Department of Commerce issued a 21-day variance Dec. 23 on the biodiesel requirement.

The suspension was designed to give fuel producers and distributors time to identify and remove any product that may be out of specification. The variance was scheduled to expire Jan. 13.

"There were quality problems at the terminal with the biodiesel supplies," said Bruce Gordon, spokesman for the Minnesota Department of Commerce. "The biodiesel fuel did not meet specifications that were set out in law, so the department issued the variance to prevent any sort of supply problem."

The fuel is typically produced from soybeans or agricultural oils and is as much as 75 percent cleaner than fossil-derived fuels. It is blended with petroleum diesel.

John Hausladen, president of the Minnesota Trucking Association, told one wire service that some of his members were "going ballistic" over the biodiesel requirement. The trucking group said that in a survey of 90 members, 56 reported problems with plugged fuel filters.

A veteran school bus maintenance supervisor has some advice for the Minnesota truckers: Go see your mechanic.

Because of biodiesels cleansing effect on fuel tanks and lines, it should not be used if filters have not been changed, says the shop supervisor. "I recommend changing filters prior to using biodiesel - and again after one tank of fuel has been run through the system. After that, maintenance schedules can proceed regularly."

The school bus maintenance chief runs a B20 blend (20 percent biodiesel) with No. 2 diesel and an anti-gel additive in temperatures as low as 25 degrees below zero on several stationary generator units and off-road vehicles - with no significant problems.

He notes that a B2 blend like that used in Minnesota (2 percent biodiesel) should not cause any problems to speak of. "Proper vehicle maintenance is very important and will resolve most issues that arise," he notes.

Anyone with biodiesel problems in Minnesota should contact the University of Minnesota Biodiesel Helpline at (651) 330-0450.