Thermal runaway is the catastrophic failure mode of a lithium-ion cell. It's a self-reinforcing cycle: heat causes chemical breakdown, which releases more heat, which accelerates breakdown. Once it starts, it cannot be stopped — only contained.
Early Warning Signs
| Sign | Severity | Action |
|---|---|---|
| Device warmer than usual during use | CAUTION | Stop vaping, let cool, monitor next session |
| Battery gets warm during charging (hot to touch) | WARNING | Unplug immediately, move to non-flammable surface, do not use |
| Hissing or popping sound from device | CRITICAL | Move outdoors away from flammables, do not handle with bare hands |
| Visible smoke or gas emission | EMERGENCY | Evacuate area, call 911, do not attempt to extinguish with water |
| Swollen or bulging battery/device body | CRITICAL | Stop use immediately, do not charge, take to battery recycling center |
If thermal runaway occurs: Do NOT throw water on a lithium battery fire — water reacts with lithium and can worsen the fire. Use a Class D fire extinguisher (designed for metal fires) or smother with sand. If you don't have either, evacuate and call 911. Move the device outdoors using tongs or thick gloves if possible — the toxic gases emitted (hydrogen fluoride, carbon monoxide) are dangerous in enclosed spaces.
