The Environmental Protection Agency is being challenged for granting three small refinery waivers to large processors. A coalition of farm groups including the National Corn Growers Association, National Farmers Union and the Renewable Fuels Association filed a lawsuit Tuesday saying the large refineries didn’t meet qualifications of the small refinery waivers. The waivers exempt the processors from compliance with annual Renewable Volume Obligations. In a statement, the farm groups say they need more transparency. In late April, EPA Administrator Scott Pruitt told reporters the small refinery exemption isn’t subjective in nature, it’s objective and is being addressed on a facility-by-facility basis.