Apart from asphyxiation/kinetic risks and cold burns from crackers (none of which are really high risk IMHO), there's also methionine synthase inactivation. The

Apart from asphyxiation/kinetic risks and cold burns from crackers (none of which are really high risk IMHO), there's also methionine synthase inactivation. The last one is what the kids need to be told about. It's unfortunately so nearly completely harmless that it catches many people by surprise that chronic use (like, daily for months for most healthy people but maybe sooner if you're low on B12) will eventually cause nerve damage. Recommended absolute minimum 2 week interval between "sessions" for long-term use.