DES MOINES, Iowa -- The Hawkeye State could be the next state to mandate biodiesel.

As Iowa lawmakers head into what could be the final week of their legislative session, still on the table is a bill that would require biodiesel blends in the state.

According to local news, the Iowa Senate passed a Biodiesel Fuel Quality Standard bill (SF 464), requiring the use of a 5 percent biodiesel blend in every gallon of diesel sold in the state.

It also provides a 3-cent-per-gallon tax credit to retailers for every gallon of diesel sold containing at least a 10 percent blend of biodiesel.

The bill must be approved by the House before going to the governor for his signature.

Minnesota, Washington, Oregon, Pennsylvania, Louisiana, New Mexico and Massachusetts have all approved biodiesel requirements -- not without initial misfueling and quality control issues.

In Canada, B.C. will be rolling out a B5 mandate on Jan. 1, 2010. Alberta and Manitoba are considering similar rules, while the federal government is committed to a national B2 mandate before 2012.

In Canada, most of the proposals are much more controversial, however, as petroleum suppliers will be required to produce "an average" biodiesel spec for their entire diesel pool, meaning higher blends will have to be produced and marketed to make up for larger customers who demand little or no biodiesel content.