Feb. 1--After a couple of sputtering starts, Minnesota's biodiesel industry has another nine days to fix problems with the fuel that may have led to trucks breaking down on the road, hefty repair bills and a lot of angst.

Biodiesel is diesel fuel made with a renewable energy source, such as soybeans. In Minnesota, it has been blamed for clogging truck fuel filters, perhaps because of high glycerin levels that gelled in cold weather.

A Minnesota law requiring diesel fuel to contain 2 percent biodiesel won't be reinstated until Feb. 10, extending an emergency waiver that would have expired in mid-January. Biodiesel advocates asked for the extension so that they could get to the root of any problems and adopt a strict quality-control plan ensuring that bad fuel won't surface again.

In Wisconsin, truckers and biodiesel suppliers are watching what happens in Minnesota. Both states have soybean industries that could benefit from widespread adoption of biodiesel.

"The positives far outweigh the negatives, especially for the Midwest," said Tony Hartmann, chief executive officer of Great Lakes BioFuels, a Madison biodiesel supplier.

But some Wisconsin trucking companies aren't so quick to embrace the alternative fuel. Several firms near the Minnesota border complained that biodiesel cost them thousands of dollars in engine breakdowns and time lost on the road.

"Even if it comes back, we are not going to put biodiesel in our trucks," said Tom Chrismer, vice president of Valley Cartage trucking in Hudson.

Valley Cartage bought biodiesel from a Minnesota supplier last fall. Shortly after, the trucking company changed about 50 fuel filters in a month as trucks ran in fits and starts.

"We aren't the only ones that had problems with this," Chrismer said. "I think it's going to take quite a while before trucking companies have confidence in biodiesel again."

There were two spates of quality problems with biodiesel in Minnesota, which is the first state to adopt a law requiring its widespread use. Some of the first problems may have come from dirty fuel storage tanks rather than the soybean blend.

Following Hurricane Katrina, diesel fuel supplies ran low nationwide. Suppliers drained their tanks, refilled them with whatever quality fuel they could find and stirred up sludge on the tank bottoms. That alone could have clogged fuel filters, said Sherry Lowe, spokeswoman for the Minnesota Soybean Growers Association.

An early winter cold snap could have caught some diesel fuel users off-guard, causing them to use the wrong blend of fuel for low temperatures. But at least some biodiesel with high glycerin levels or some other problem was distributed in Minnesota as truckers already were upset about the first problems.

"It was a very sad, unfortunate event when we were trying so hard to do something so good," Lowe said.

Soybean growers say they don't know how much biodiesel made at improper specifications was delivered in Minnesota. They aren't sure where it came from, either, which has made it difficult to convince truckers that the problems have been solved.

State officials are sampling fuel supplies and digging into clogged fuel filters for evidence of what went wrong. The National Biodiesel Board, based in Jefferson City, Mo., also has become involved.

"There's no room for poor-quality biodiesel in the marketplace," said Steve Howell, technical director.

"Although investigations have indicated that other factors unrelated to biodiesel may have led to at least some of the filter- plugging reports in Minnesota, there's no question that off- specification biodiesel can have a severe reaction in cold weather, even in low blends," Howell said.

Wisconsin wants to jumpstart more investments in biodiesel, ethanol and other renewable energy under a $1 million grant program announced by Gov. Jim Doyle in December. So far, the state has not experienced problems with biodiesel, truckers and state officials said.

But with any new technology, it's not unusual to have "hiccups" in the early stages, Hartmann said.

"The new (biodiesel) plants in Minnesota are using some competing technologies. As they come online, there's going to be a shakeout period," he said.

It's also not unusual for fuel filters to clog when switching to biodiesel because the fuel dissolves gunk trapped in a fuel system and washes it into a filter, where it's trapped and removed. The clogging should end after a few filter changes, biodiesel advocates said.

But for many reasons, including highway safety, truckers say they can't afford roadside breakdowns because of clogged filters. They also can't afford lost road time while their vehicles are in the shop for filter changes.

"It's simply not acceptable," Chrismer said. "I can't flip a coin and hope" that trucks will have enough power to climb a steep hill.

The Minnesota problems were sporadic, which has made them puzzling.

Many trucking firms didn't have clogged filters or engine performance issues. Still, 62 percent of the Minnesota Trucking Association's fleet managers who responded to a December survey reported clogged fuel filters, engines failing to start, power loss on hills and roadside breakdowns.

Seven of nine trucks would not start during a cold snap at a trucking terminal owned by Lakeville Motor Express of Roseville, Minn.

"I have a pretty damn good hunch" it was related to biodiesel, said Oscar Torgeson, fleet maintenance manager.

But the problems have been exaggerated by truckers who oppose the biodiesel mandate, said Lowe of the soybean growers association. A coalition of industries that use diesel fuel, led by truckers, tried to block the Minnesota legislation over fears of higher fuel costs, supply shortages and performance issues.

Lowe said she fears that biodiesel will be wrongly blamed for problems after the emergency waiver is lifted and the fuel comes back.

"That's an unsubstantiated, mean-spirited way to continue to try and get rid of the mandate," she said.

The Minnesota Trucking Association isn't against biodiesel, though it opposed the mandate, said President John Hausladen. Truckers still are not confident that Minnesota's biodiesel dilemma has been solved, partly because they haven't been told exactly what went wrong.

"Are we hopeful? Yes. But at this point, we have no data or factual basis to be confident," Hausladen said.

The next introduction of biodiesel in Minnesota needs to be perfect, or close to it, to silence critics. The Minnesota Soybean Growers Association has recommended sanctions against biodiesel suppliers and handlers who introduce bad fuel into the marketplace.

"All of the rest of the states are watching what happens with this," Lowe said. "Unfortunately for us and fortunately for them, they're going to know exactly what not to do."

A recycling company is building Wisconsin's first biodiesel refinery in DeForest. To avoid repeating Minnesota's problems, biodiesel advocates here are calling for quality-control standards set by the National Biodiesel Board that are voluntary.

"It's not that biodiesel didn't work in Minnesota. It's just that they had some problems," Hartmann said. "They had two hiccups right out of the gate."