In a car accident how often are injuries caused by the air bag?

Minor ones common. Very minor ones are common. These include eye irritation, minor flash burns, and sometimes finger fractures if the steering wheel is not being held properly (8 and 4 o'clock preferred). All are easily managed. Serious injuries are rare. However, injuries that occur without an airbag (brain, face, neck) can be devastating, so make sure your airbag is activated if appropriate for your weight.