>Michelle.
>
>Sure, it'll kill you dead if you breath enough in.
>
>Oxygen is also extremely toxic as well. Too much of that and you'll burn up - literally if you get a spark.
>
>I think we breath in something like 65% hydrogen, the rest mostly oxygen and some trace stuff.
>
>Best,
>
>DD
>
>>Carbon dioxide is toxic? I know it contributes to the greenhouse effect, but I didn't think it was toxic... Or did I just fall for something? :)
>>
>>Michelle
>>
>>
>>>
>>>I took a look at the site. I can't say if it's serious or not, but it appears to be serious. If it is, as far as I'm concerned, those guys suffer from paranoia...
>>>
>>>While they're at it, they should be concerned by human breathing: we do release toxic carbon dioxyde! :) The only solution: stop breathing!

CO2 is not toxic, it is just that a lung full of CO2 is a lung without O2. It is the absence of O2 that kills you. Additionally, CO2 in the lung is required for the signal to your brain to breath. Of course, at high pressures even normally benign gasses can be toxic eg. nitrogen narcosis.