In the thread begun by our very own Circus Strongman, the AMAZING Dan Lurie, I had wondered about the deployment of the airbag and the smell that AMAZING reported made him think the car was on fire. A smell so string and convincing that he was HIGHLY motivated to exit the vehicle, which he did by literally tearing the door off it's hinges and throwing it across the road. Adrenaline and gamma-irradiated Circus Strongman muscles make a potent combination!
Anyway, I did about 20 seconds of in depth research on Google investigating the subject, and I have prepared the following multiple paragraph report:
The solid propellant used in an airbag inflator typically contains sodium azide (NaN3) often used as a solid rocket propellant, iron oxide (Fe2O3), and small amount of other proprietary additives. An alternative formulation is cellulose nitrate (guncotton), hexogen (RDX) and octogen HMX) but I don't know if this formulation is actually in use or was simply a test formula. Both RDX and HMX are high explosives - which is not to say that sodium azide is any slouch in the BANG! department.
When a car is involved in a crash severe enough to activate the sensing unit(s), an electrical charge is routed to the gas generator, which ignites the fuel. The fuel then creates a tremendous amount of inert nitrogen gas filling the airbag. Note that there is no nitrogen oxide as I had originally speculated.
The total elapsed time from contact to full deployment of the airbag will vary, but it should deploy within 1/25 second. The principle gas product as the result of the combustion of the NaN3/Fe2O3 propellant is nitrogen, and the resulting temperature is in the neighborhood of 1880 F. Solid compounds such as sodium oxide (Na2O) and ferrous oxide (FeO) are also generated during the combustion process.
End of report.
Don't get all likkered up and go tearing about town in you Hupmobile! There are EXPLOSIVES packed into your steering wheel, for christsakes!