State pollution control officials have taken 20 enforcement actions against ethanol plants in the past six years for air or water pollution, including six plants that were cited more than once. Here are the five largest penalties.

Plant City Penalty Year Violation

Minnesota Energy Buffalo Lake $1,150,000 2009 Water

Corn Plus* Winnebago $1,041,000 2009 Air

Bushmills Ethanol Atwater $ 800,000 2012 Water/air

Corn Plus* Winnebago $ 760,000 2011 Water

Bushmills Ethanol Atwater $ 425,000 2009 Water/air

* includes federal and state penalties. Source: Minnesota Pollution Control Agency, Star Tribune research