Mealey's (January 28, 2019, 2:02 PM EST) -- MADISON, Wis. — The Wisconsin Supreme Court majority on Jan. 25 determined that a pollution liability insurer breached its duty to defend an additional insured for underlying property damage claims arising out of a sewage backup and said that the additional insured’s defense costs, which were paid by another insurer, must be allocated on a pro rata basis between the two insurers (Steadfast Insurance Co. v. Greenwich Insurance Co., No. 2016AP1631, Wis. Sup., 2019 Wisc. LEXIS 9)....