UN 0503 — Air bag inflators or Air bag modules
Placard: Explosive 1.4G. ERG Guide 114. Training/quick-reference only — use current ERG + SOP/SOG for incident-specific actions.
UN 0503 is Air bag inflators or Air bag modules, a Class 1.4G pyrotechnic safety-device entry assigned to ERG Guide 114. It covers air bag inflators or modules that can actuate, rupture or release smoke when heated or damaged.
Hazard overview: UN 0503 presents a limited pyrotechnic and pressure-device hazard. Heat or fire can cause inflators to deploy, rupture or scatter fragments, while smoke from burning modules may contain irritating or toxic combustion products.
Response guidance: For a UN 0503 incident, responders should confirm the shipment using markings, shipping papers and ERG Guide 114. Isolate the area, keep personnel out of smoke, avoid handling damaged or heated modules and cool exposures only from a safe position under incident command.
Firefighter training notes: Training should emphasize the difference between limited-effect explosives and higher-hazard Class 1 materials. Common errors include standing too close to heated packages, dismissing smoke hazards, disturbing damaged articles and failing to check for adjacent explosives or ammunition.
Regulatory context: Air bag inflators or Air bag modules is regulated as a Class 1 explosive hazardous material. Transportation, storage, quantity limits, fire code controls and reporting requirements may vary by jurisdiction. Responders should verify current requirements through shipping papers, SDS or product documents and applicable DOT, ATF, OSHA, NFPA, military, state or local authority guidance.
Storage & handling: Air bag inflators or Air bag modules should be stored only in approved packaging, magazines or authorized explosive storage areas, separated from ignition sources, incompatible materials and unauthorized access. Packages should be protected from heat, impact, friction, moisture where relevant and physical damage according to product documentation and applicable explosive storage regulations.
UN 0503 Quick Details
Common Hazards of UN 0503
- Limited pyrotechnic and pressure-device hazard from inflators or modules.
- Heat or fire may cause inflators to actuate, rupture or project fragments.
- Smoke from burning modules may contain irritating or toxic combustion products.
- Low mass explosion risk under normal transport conditions.
- Damaged modules may contain sharp metal housings, undeployed inflators or pyrotechnic residue.
- Vehicle fires or bulk storage can increase the number of devices involved.
Chemical Identity & Physical Properties
Metal cylindrical or rectangular assemblies containing solid pyrotechnic propellant (typically sodium azide or guanidine nitrate). Devices are typically gray or black metal housings, inert until activated.
| Also known as | Air bag inflatorsAir bag modulesPyrotechnic inflatorsSupplemental restraint system inflatorsSRS inflators |
| Appearance | Metal cylindrical or rectangular assemblies containing solid pyrotechnic propellant (typically sodium azide or guanidine nitrate). Devices are typically gray or black metal housings, inert until activated. |
| Flash Point | Not applicable (pyrotechnic device) |
| Boiling Point | Not applicable (pyrotechnic device) |
| Vapor Density | Not applicable (solid pyrotechnic device) |
| Water Reactivity | No significant reaction with water. Sodium azide residue may produce toxic hydrazoic acid gas if wetted. |
Fireground Response Guidance — UN 0503
Extinguishing Media
PPE Requirements
Structural firefighting protective clothing with SCBA is appropriate for fire or smoke exposure, with distance maintained from heated packages. Approach and handling should follow incident command and local SOP.
Isolation & Evacuation
First Actions for a UN 0503 Incident
- CALL 911. Notify law enforcement if explosive articles, ordnance or pyrotechnic devices are involved.
- Keep unauthorized personnel away.
- Stage upwind and avoid smoke from burning articles.
- Move unprotected people out of the smoke path when safe and practical.
- Eliminate ignition sources if it is safe to do so.
- Isolate the area and expand the perimeter if fire grows or additional explosives are present.
- Use ERG Guide 114, shipping papers and incident command for isolation and fire response decisions.
📋 Copy & Share Field Card
UN 0503 — Air bag inflators or Air bag modulesUse for: Quick radio or face-to-face size-up. Short, structured, field-ready.
Use for: Incident command briefing, staging area whiteboard, or pre-entry team brief.
Use for: Quick text to command or incoming units. Fits in a single SMS.