A、Because carbon dioxide dilutes the oxygen concentration in the atmosphere and may cause asphyxiation
B、Because carbon dioxide breaks down in a fire into carbon monoxide which may cause blood poisoning in the person breathing this gas
C、Because carbon dioxide is a colorless and odorless gas that becomes highly toxic in the presence of high temperatures and will quickly incapacitate a person exposed to this gas
D、This action is unnecessary as carbon dioxide is not poisonous nor toxic but is a relatively harmless ga