Loc Nar Co2 deadly? Are you sure your not thinking about carbon monoxide which I have read on here is usable in a box during seedling stage to promote females. Carbon Dioxide can't be that deadly to humans as we drink it in fizzy juice although it is part of what causes the stale air taste in aeroplanes. I agree you would have to watch the medium being used to create the Co2 if you have young children or pets as some of the tablets or microbes used could probably have dangerous effects & I wouldn't recommend taking a blast from a bottle regulator.