The nation's heaviest ethanol-producing states have asked the U.S. Supreme Court to overturn a California law they say discriminates against out-of-state ethanol fuel.

Attorneys general for 21 states filed a legal brief on April 21 asking the high court to overturn California's low carbon fuels standard (LCFS), which assigns a high-carbon value to ethanol because it must be brought in by interstate commerce, reports Biomass Magazine.

The states joined two biofuels lobby groups that filed a similar legal brief in March. The states who signed off on the April 21 filing include Alabama, Alaska, Arizona, Georgia, Illinois, Indiana, Iowa, Kansas, Michigan, Missouri, Montana, Nebraska, North Dakota, Ohio, Oklahoma, South Carolina, South Dakota, Texas, Utah, West Virginia and Wyoming.