HALIFAX — After nearly two years of running biodiesel in a fleet of buses, something is starting to smell fishy in the city of Halifax.

The city quit using a unique B20 (20 percent biodiesel 80 percent petrol diesel) blend of fish oil-based biodiesel in its fleet of municipal buses this past December after encountering some operational difficulties, reports the Halifax Chronicle Herald.

Paul Beauchamp, general manager of fleet, told the newspaper that the buses were not running properly — “stalling, not starting, those sorts of things.” He said that over time, a sticky substance started to clog the fuel system.

Although higher concentrations of biodiesel has been known to gel in the winter, Beauchamp said he doesn’t think cold weather was the problem since some buses experienced problems in August as well.

According to the Herald, the municipally took up the issue with its supplier Wilson Fuel Co., which denied a problem with the fuel existed. The company blamed the buses’ engines.

Therefore the city has halted use of the biodiesel until the problem is resolved. “We just have to find what the proper mixture is for this to work properly for us,” Beauchamp told the paper.

In the meantime, the fuel company will continue to supply the city with petroleum diesel.

— with files from the Chronicle Herald