First, some basics. Most disposable hand warmers contain a mix of iron, water, activated carbon, vermiculite, cellulose, and salt. Once exposed to air, the iron oxidizes and releases heat in the process. After all the iron has reacted, the hand warmer is done and ready for the trash.

Are hand warmers bad for you?

Once the hand warmer is used, it is no longer considered toxic, as the iron is essentially considered "inactivated." However, if it is an unused packet, then it can be quite dangerous depending on the amount ingested. Iron toxicity can vary from mild to severe - at its worst it can be fatal.

How long do hand warmers take to activate?

Quantity: 160 Individual Hand Warmers (80 pairs). Duration OF Heat: Up to 10 hours of heat. Activation Time: 15-30 minutes.