Especially in the evening, it appears that the south side of McPherson is home to a city of lights, many stories high and many acres wide. What you're seeing is one of two oil refineries owned by CHS, the nation's largest farmer-owned cooperative refinery. It processes about 95,000 barrels of crude oil each day, and the majority of it comes from Kansas producers. The crude oil is refined into gasoline and diesel fuel products for distribution in the central and northern United States.