One of the disadvantages of using carbon dioxide to extinguish a fire in an enclosed space is
A.the ‘snow’ which is sometimes discharged along with the gas is toxic
B.prolonged exposure to high concentrations of CO2 gas causes suffocation
C.rapid dissipation of the CO2 vapor
D.the CO2 gas is lighter than air and a large amount is required to extinguish a fire near the deck
正确答案：B
