I believe sodium azide is used commonly for airbag inflation charges. It may be part of a mixture that is vendor specific though.
Takata uses cheaper ammonium nitrate - the same thing used on the Federal Building in Oklahoma City - which would probably be ok if it wasn’t subjected to heat and humidity.
“by 2001 Takata had switched to an alternative formula, ammonium nitrate” http://www.nytimes.com/2014/11/20/business/takatas-switch-to-cheaper-airbag-propellant-is-at-center-of-crisis.html