Editing Airbag (section)

==== Inflation ====
{{one source | section|date=May 2016}}
When the frontal airbags are to deploy, a signal is sent to the [[gas generator|inflator unit]] within the airbag control unit. An igniter starts a rapid [[chemical reaction]] generating primarily [[nitrogen]] gas (N<sub>2</sub>) to fill the airbag making it deploy through the module cover. Some airbag technologies use compressed [[nitrogen]] or [[argon]] gas with a pyrotechnic operated valve ("hybrid gas generator"), while other technologies use various energetic [[propellant]]s. Although propellants containing the highly toxic [[sodium azide]] (NaN<sub>3</sub>) were common in early inflator designs, little to no toxic sodium azide has been found on used airbags.

The azide-containing pyrotechnic gas generators contain a substantial amount of the propellant. The driver-side airbag would contain a canister containing about 50 grams of sodium azide. The passenger side container holds about 200&nbsp;grams of sodium azide.<ref>{{cite web|url= http://www.sdearthtimes.com/et0800/et0800s9.html |title=ET 08/00: Sodium azide in car airbags poses a growing environmental hazard |website=sdearthtimes.com |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20140917155736/http://www.sdearthtimes.com/et0800/et0800s9.html |archive-date=17 September 2014 }}</ref>{{better source needed|date=May 2016}}{{better source needed|date=May 2016}}

The alternative propellants may incorporate, for example, a combination of [[nitroguanidine]], phase-stabilized [[ammonium nitrate]] (NH<sub>4</sub>NO<sub>3</sub>) or another nonmetallic oxidizer, and a nitrogen-rich fuel different from azide (e.g. [[tetrazole]]s, [[triazole]]s, and their salts). The burn rate modifiers in the mixture may be an alkaline metal [[nitrate]] (NO<sub>3</sub>-) or [[nitrite]] (NO<sub>2</sub>-), [[dicyanamide]] or its salts, [[sodium borohydride]] (NaBH<sub>4</sub>), etc. The coolants and [[slag]] formers may be e.g. [[clay]], [[silica]], [[alumina]], glass, etc.<ref>{{cite web |url= http://www.freepatentsonline.com/6306232.html |title=Thermally stable nonazide automotive airbag propellants – Patent 6306232 |website=freepatentsonline.com |access-date=16 March 2014 |url-status=live |archive-url= https://web.archive.org/web/20140316213602/http://www.freepatentsonline.com/6306232.html |archive-date=16 March 2014}}{{primary source inline|date=May 2016}}</ref>{{better source needed|date=May 2016}}{{primary source inline|date=May 2016}}{{Original research inline|date=May 2016}} Other alternatives are e.g. [[nitrocellulose]] based propellants (which have high gas yield but bad storage stability, and their [[oxygen balance]] requires secondary oxidation of the reaction products to avoid buildup of carbon monoxide), or high-oxygen nitrogen-free organic compounds with inorganic oxidizers (e.g., di or tri[[carboxylic acid]]s with [[chlorate]]s (ClO<sub>3</sub>-) or [[perchlorate]]s (ClO<sub>4</sub>-) and eventually metallic oxides; the nitrogen-free formulation avoids formation of toxic [[nitrogen oxide]]s).

From the onset of the crash, the entire deployment and inflation process is about 0.04 seconds. Because vehicles change speed so quickly in a crash, airbags must inflate rapidly to reduce the risk of the occupant hitting the vehicle's interior.<ref>{{Cite web |title=Airbags |url=https://www.iihs.org/topics/airbags |access-date=2025-04-24 |website=IIHS-HLDI crash testing and highway safety |language=en}}</ref><ref>{{Cite web |title=How do air bags work? |url=https://www.scientificamerican.com/article/how-do-air-bags-work/ |access-date=2025-04-24 |website=Scientific American |language=en}}</ref>