^ Yep, explosions can happen without combustibles.

Anyway, no probs with them in my saddle bag in 95F heat, nor with a new box of Daisy CO2 cartridges sitting on my doorstep in the hot sun. I'll find out how they hold up at 14,265' or so this summer. The box says don't heat above 140F, but the cartridges themselves say 120F (WTF?). Anyhow, I'm pointing them forward in my saddle bag so that if they do burst and act like missiles, I'll get a boost.