Correct CO2 reference data
Correct CO2 reference data

5000ppm of CO2 is not deadly, you're thinking of >5%, which would be 50 000ppm. 
5000ppm is actually the permissible exposure limit set by the US Occupational Safety and Health Administration (OSHA) for an eight hour work day. 30 000ppm is defined as a ceiling exposure limit for 10 minutes. 4% can lead to intoxication, ~7% to unconsciousness, ~9% over 5 minutes may lead to death.  Source: http://www.blm.gov/style/medialib/blm/wy/information/NEPA/cfodocs/howell.Par.2800.File.dat/25apxC.pdf (which has some extra data and references)
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