The U.S. Environmental Protection Agency agreed to conduct a long-delayed study to assess the impact that burning ethanol as a motor vehicle fuel has on air quality, according to a Reuters report.

The Sierra Club, arguing the study should have been done eight years ago, filed a lawsuit in 2018 to force the EPA to conduct the study. The parties reached a partial agreement, with the EPA agreeing to conduct the study by March of 2020.

The results of the study could affect the federal Renewable Fuel Standard, which mandates the amounts of ethanol blended into the nation’s fuel supply each year.