Commercial general liability insurance operates on one of two fundamental coverage triggers, and understanding the distinction between occurrence-based and claims-made coverage stands as essential knowledge for any professional advising on commercial insurance matters. The occurrence-based trigger, which forms the predominant structure for commercial general liability policies across Canada, determines coverage not by when a claim is filed but by when the bodily injury or property damage actually takes place. This seemingly straightforward principle becomes remarkably complex when applied to injuries or damages that develop gradually over extended periods, span multiple policy years, or manifest long after the conduct that caused them. For Canadian insurers, policyholders, brokers, and risk managers, the treatment of claims that develop over time represents one of the most challenging aspects of commercial general liability coverage, demanding careful attention to policy language, provincial jurisprudence, and the evolving understanding of what constitutes an occurrence.
The legal foundation for occurrence-based coverage in Canada derives from the standard form commercial general liability policy, which has undergone numerous revisions over decades of use. The Insurance Bureau of Canada publishes standard commercial general liability forms that serve as the template for most policies issued in British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, and the Atlantic provinces. These standard forms define occurrence in substantially similar language across jurisdictions, typically stating that an occurrence means an accident, including continuous or repeated exposure to conditions, which results in bodily injury or property damage neither expected nor intended from the standpoint of the insured. This definition, deceptively simple on its surface, contains within it the seeds of considerable interpretive difficulty when courts must determine precisely when an occurrence takes place for purposes of triggering coverage. Quebec operates under a distinct insurance regime governed by the Civil Code of Quebec, though commercial liability policies issued in that province generally incorporate similar occurrence language adapted to the civil law framework. As of the date of authorship, the standard IBC CGL form remains the dominant template, though individual insurers frequently modify standard language through proprietary forms or manuscript endorsements.