Weyerhaeuser Co. v. Commercial Union Ins.

Summary

The Washington Supreme Court, sitting en banc, resolved a coverage dispute between Weyerhaeuser and Commercial Union (CU), the sole nonsettling successor excess insurer, over environmental cleanup liability at multiple hazardous waste sites. The court held the supplemental excess policy contains no property damage aggregate limit but entitles CU to a $500,000 per-incident setoff; CU may not offset settlements Weyerhaeuser received from other insurers because the insurer bears the burden of proving a double recovery; the policy covers property damage occurring during the policy period even where caused by third parties and the insured's statutory liability arose from later waste shipments; expert testimony on Mid State damages was properly admitted; prejudgment interest runs on liquidated invoice-based cleanup costs but not on unliquidated damages or attorneys' fees; and consent-decree payments functionally exhaust the underlying policy so as to trigger the excess insurer's duty to defend, though a material fact question about premature tender required remand. The court affirmed in part, reversed in part, and remanded, awarding Weyerhaeuser appellate attorneys' fees.