Aggregate Limits Do Not Apply to Environmental Claims, Ninth Circuit Rules

Why It Matters

The ruling can dramatically increase insurer exposure on long‑tail environmental claims and signals that ambiguous limit clauses will be interpreted in favor of coverage, reshaping risk assessments for legacy policies.

Key Takeaways

• Ninth Circuit rules aggregate limits don’t apply to property‑damage claims
• Ambiguous CGL language interpreted in policyholder’s favor under contract law
• Pre‑1986 CGL policies often omitted aggregate limits for premises‑operations
• Policyholders should examine drafting history to counter insurer denials
• Long‑tail environmental claims can exceed hundreds of millions without aggregate caps

Pulse Analysis

The Ninth Circuit’s decision in County of San Bernardino v. Insurance Company of the State of Pennsylvania revives a long‑standing debate over aggregate limits in commercial general liability (CGL) policies issued before the 1986 industry overhaul. The court examined three umbrella policies from 1966‑1975 covering hazardous waste disposal at the Chino Airport, where the county faces cleanup costs that could top $400 million. By holding that the aggregate‑limit clause was ambiguous and therefore not applicable to property‑damage claims, the judges opened the door for insurers to be liable on a per‑occurrence basis, potentially multiplying exposure across multiple years.

The panel applied the classic ambiguity doctrine: when a contract term admits two reasonable constructions, it is read against the drafter. Extrinsic evidence—including internal ISPT memos and industry drafting history—showed that insurers historically treated premises‑operations, especially environmental, claims as outside aggregate caps. Although the court did not weigh that evidence as decisive, it reinforced the notion that pre‑1986 CGL forms were drafted without a universal aggregate limit. This interpretation aligns with the 1986 Congressional report and ISO revisions that later standardized aggregate limits for product liability but not for environmental property damage.

For policyholders, the ruling underscores the importance of digging into policy language and the surrounding drafting history during discovery. Companies with legacy CGL coverage should audit each policy year for separate aggregate provisions and consider leveraging internal insurer documents to challenge blanket limit defenses. Insurers, meanwhile, may need to revisit underwriting practices for long‑tail exposures and clarify limit language in renewal forms. As environmental and product‑liability claims continue to rise, the decision provides a powerful tool for claimants to secure broader coverage and for counsel to anticipate potential liability spikes.