Did something else happen after the first mistake that really caused the harm? A superseding cause is an unexpected, independent event that breaks the chain between an earlier act and the final injury or damage. When a court finds a superseding cause, the person or business that acted first may not be legally responsible for what happened later, because the later event is treated as the real cause. The key fight is usually over foreseeability: if the later event was a normal risk of the first act, it may not cut off liability. If it was extraordinary or abnormal, it might.

This can become a trap in injury claims because insurers often try to blame a later event to avoid paying. In a car crash case, for example, they may argue that bad weather, a second collision, or a third person's conduct was the true cause of the injury. On upstate highways, black ice from October through April - especially on the I-90 Thruway near Rochester - may be raised as part of that argument. But slippery conditions are not always so unusual that they erase an earlier driver's negligence.

In New York, whether a superseding cause exists usually turns on case law and facts, not a fixed statute or deadline. It can directly affect causation, comparative negligence, and the value of a personal injury claim. If the defense can successfully label a later event as superseding, compensation may be reduced or denied altogether.