The 1st District Appellate Court, reversing the trial court, recently held that an insurer, relying on an exclusion to additional insured coverage, failed to affirmatively establish applicability of the exclusion, and therefore owed a duty to defend the additional insured.The insurer in Hastings Mutual Insurance Co. v. Blinderman Construction Co., 2017 IL App (1st) 162234 (Oct. 24), was represented by Mulherin, Rehfeldt & Varchetto of Wheaton. Cremer, Spina, Shaughnessy, Jansen & Siegert represented the additional …