(October 31, 2018, 1:29 PM EDT) -- CHICAGO — The owner of the largest natural gas processing facility in the United States on Oct. 29 agreed to pay a $2.7 million civil penalty and spend $4.5 million on improvements to its pollution controls to resolve allegations brought by the federal government in Illinois federal court that it violated the Clean Air Act (CAA) (United States v. Aux Sable Liquid Products LP, No. 18cv7198, N.D. Ill.)....