The term "accident" can be defined as an unplanned event that interrupts the completion of an activity, and that may (or may not) include injury or property damage. Accident investigations are conducted to find out the cause(s) of accidents and to prevent similar accidents in the future. When accidents are investigated, the emphasis should be concentrated on finding the root cause(s) of the accident rather than the investigation procedure itself. The best team to conduct an accident investigation includes the injured worker, their supervisor and a safety representative. It is critical that the injured worker?s supervisor is on the accident investigation team because this person will be the most knowledgeable about the work conditions and the people involved. This article covers many models of accident causation, ranging from Heinrich's domino theory to the sophisticated Management Oversight and Risk Tree (MORT). However, it is essential to remember that the purpose of an accident investigation is to determine the cause(s) of the incident and to implement corrective actions in order to prevent this accident from happening again. A thorough accident investigation is always worth the time and effort!