The MSR Reactor actually went through a recall because of a test Backpacking Light did that revealed very dangerous levels of CO2 it was giving off... they fixed the problem in newer stoves. People frequently ignore "do not use in a tent" warnings. The original Pocket Rocket gave off enough CO2 to cause a headache.

I'm pretty sure outdoor use disperses what little is there... but, I'm still pretty happy the Giga is rated one of the lowest CO2 makers on the list.

"In the beginner's mind there are many possibilities. In the expert's mind there are few." Shunryu Suzuki