I left my home with my daughter in the afternoon to go to the bank and hardware store. I drove to the bank to make a deposit. We had to wait for quite awhile in the drive-through line at the bank, so I turned off my engine a couple of times rather than having the car idle. After making the deposit at the bank, I pulled out of the bank lot and began driving to the hardware store. I had driven for about two minutes and was driving along at approximately 25-30 miles an hour, and suddenly there was a terrible explosion at my left ear and massive pain in my left arm. I thought the car had been shot at and my arm hit. I was terrified we were still being shot at and looked at my daughter whose hands were over her ears. I could tell by that time that I was not bleeding and so was worried that the bullet had hit her. I could hear only faintly out of my left ear. There was smoke and the smell of an explosion. I could see by this time that an airbag had come out of my driver's seat and thought that it had been hit too. My daughter told me she was o.k. and to pull the car over so that we could see what had happened. I was shaking with fear and pain in my arm but finally calmed down enough to park the car and get out to see what had happened. It became clear that the car had not been shot at and that the driver's side seat airbag had simply spontaneously exploded without any warning whatsoever. The driver's seat side seam was completely ripped, multiple pieces of seat foam were lying a