What is co2 fire exstinguishers used for and not used for?

CO2 fire extinguishers are primarily used for extinguishing Class B fires (flammable liquids) and Class C fires (electrical fires) due to their ability to displace oxygen and cool the flames without leaving a residue. However, they are not suitable for Class A fires (ordinary combustibles like wood, paper, and cloth) because they do not cool the material sufficiently, potentially allowing the fire to reignite. Additionally, they are ineffective against Class D fires (combustible metals) and should not be used in confined spaces without proper ventilation, as the CO2 can displace breathable air.