An action over endorsement removes the employer's liability exclusion from your general liability policy for specific third-party-over claims. Here is the scenario it addresses: one of your roofing employees is injured on a job, collects workers compensation benefits, and then sues the general contractor or property owner for negligence. That third party turns around and sues you (the employer) for contribution or indemnification, claiming your negligence caused the employee's injury. This is called an "action over" or "third-party-over" claim.
Your standard CGL policy contains an employer's liability exclusion that bars coverage for bodily injury to your own employees. Without the action over endorsement, this exclusion would also block coverage for the GC's cross-claim against you, leaving you to defend yourself out of pocket. The action over endorsement carves back coverage specifically for these third-party-over suits, allowing your CGL to respond when a GC or owner seeks contribution from you after being sued by your injured employee.
This endorsement is particularly important for roofing contractors because of the high injury rate in roofing work. Falls, burns, and equipment injuries frequently result in workers comp claims that escalate into third-party lawsuits. Some states with labor laws that impose strict liability on property owners and GCs for gravity-related injuries, such as New York's Labor Law 240, make action over endorsements essential. If you work on commercial projects where GCs require indemnification, discuss this endorsement with your broker.