In late 2017, Sierra Club sued the EPA over failure to provide to Congress research on the environmental effects of the Renewable Fuel Standard (RFS) as required by law. The lawsuit alleged that, among other things, increased emissions from high ethanol content fuel caused respiratory issues in one of its California members. In response to the lawsuit, Urban Air Initiative (UAI), a Kansas-based non-profit promoting cleaner air and reduced emissions through increasing ethanol blended into gasoline, filed an amicus brief refuting many of the claims in the Sierra Club lawsuit, but still asking that the EPA complete the required research. Late last month, Sierra Club and the EPA agreed to partially settle the lawsuit. The EPA will perform an anti-backsliding study on the impact of ethanol for vehicle fuel by March 2020.
Here is the original Sierra Club lawsuit complaint:sc_complaint_10192017
Here is a UAI Article regarding the lawsuit.
Here is a UAI Amicus Brief about the lawsuit:20180405-Proposed-Amicus-Brief
Here is a Reuters Article summarizing the partial settlement.