"And lead is only an element and not a poison. Would you think this even if your kid breaths it in from paint dust at the old school she attends?"
A human being could easily survive in a world with 18% oxygen and much, much greater CO2 concentration than what exists now with no harmful effects whatsoever if that is the question.
CO2 needs to be in much higher concentration to harm someone than the concentrations we are talking about for manmade global warming.
It is totally inappropriate to compare the toxic effects of tetraethyl lead and CO2. Lead stays in your body and does damage once ingested. CO2 comes and goes every time you breathe. In fact you are producing the stuff right now. Are you dead yet?