[coolguy4]

The problem is your statement is that CO2 is not poisonous. It is a natural gas that is produced by human breath.

It is also not dirty. We're not talking about particles of carbon in the air, we're talking about CO2, an odorless, invisible gas.

[jimjimjim]

The dose makes the poison.

If you are thirsty and you become trapped underwater, you don't just get extremely refreshed!

[ericd]

Coal puts out a lot other pollutants that are poisonous. Coal kills far more people than nuclear.