Is the blue gel in ice pack poisonous?

Food Science: Does reusable gel pack ice last longer than normal water ice (if it was packed the same way)? How much so?

• Answer:

  AFAIK, gel packs are mostly water with just a little bit of gelling agent. It's hard to improve on melting ice for heat capacity and non-toxicity. So it ought to be much the same weight for weight. Update: This page, http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1043&context=it_fac reports values from 314 to 418 kJ/kg (cf. plain ice at 334). So there's not a huge amount of degradation, and some formulations are even better weight for weight.