During July 1995, an infant in southeast Louisiana died as a result of heat exposure in an enclosed automobile. To evaluate degree of heat exposure in a vehicle, we compared the temperature rise inside an enclosed, dark-colored vehicle with the temperature rise in light-colored vehicle with the windows partly open. Within 20 minutes, readings in both cars exceeded 125 degrees F and reached approximately 140 degrees F in 40 minutes--a temperature rise of over 45 degrees F. A person who is unable to remove himself from an enclosed vehicle is at risk for a life-threatening crisis if left alone in a sun-exposed car for even a relatively short period of time.