2000 SAAB 9-3 Seats Problems

The driver's side, side air bag deployed spontaneously. There was no apparent reason or cause, ie no side impact of any kind, no door slamming or other provocation. The car was parked in a garage for six hours before I sat in the car, closed the door, then BLAM! Temperature was moderate, where as the car is often parked on a city street in direct sun. Air bag deployment was a loud bang followed by smoke from an explosive, and a sting on my neck and shoulder where the bag hit me. Bits of foam from the seat interior, where the air bag was located, blew around the car interior. I suffered temporary hearing loss in my left ear due to the loud bang. I was also quite startled. No other people were at risk. No other air bags have deployed since I've owned the car, approx. 20 yrs., purchased...