Mealey's (July 23, 2015, 11:59 AM EDT) -- BALTIMORE — A commercial general liability insurer has a duty to defend an insured in an underlying action because the alleged property damage, as the result of the insured’s failed water treatment in a heating, venting and air conditioning (HVAC) system, constitutes an “occurrence,” a Maryland federal judge ruled July 16 (State Automobile Mutual Insurance Co. v. Old Republic Insurance Co., et al., No. 14-2989, D. Md.; 2015 U.S. Dist. LEXIS 92707)....