Real world motor vehicle collision research of injuries due to deployment of "first-generation" air bags has been conducted by Transport Canada since 1993. Fifty-three fatal crashes (36 frontal impacts; 17 side collisions) involving 48 drivers and 10 right front passengers were reviewed. In the Canadian data, air bag deployment in five of nine low severity frontal crashes (delta-V (deltaV) < 25 km/h or 15 mph) was linked to five deaths, four of whom were autopsied (four adults with craniocervical (basal skull and C2 fracture with brainstem avulsion; "closed head injury"--no autopsy) or chest trauma (aortic or pulmonary artery tears); one child with atlanto-occipital dislocation). An occupant who is close ("out-of-position") to the air bag at the time of deployment is at risk for injury. In 27 high severity frontal impacts, unusual (e.g., pulmonary "blast" hemorrhage in one autopsied case) or isolated potentially survivable injuries (e.g., clinically documented ruptured right atrium; probable flail chest observed during the autopsy on a decomposed body) localized to the head, neck or chest in three possibly out-of-position drivers pointed to the deployed air bag as a source of injury. In one of 17 side collisions an out-of-position driver sustained a radiographically confirmed C1-C2 dislocation in a minimally intruded vehicle.