Mealey's (April 28, 2017, 4:00 PM EDT) -- SEATTLE — The majority of the Washington Supreme Court on April 27 determined that an insurer has a duty to defend underlying claims arising out of carbon monoxide poisoning because the efficient proximate cause of the loss was the negligent installation of a hot water heater, which is a covered occurrence under the policy (Zhaoyun Xia, et al. v. ProBuilders Specialty Insurance Co., et al., No. 92436-8, Wash. Sup., 2017 Wash. LEXIS 443)....