Why are ordinary carbon-dioxide fire extinguishers unsuitable for sodium fires?

Ordinary carbon-dioxide fire extinguishers are unsuitable for sodium fires because sodium reacts with carbon dioxide.1

When sodium burns, it reaches temperatures exceeding 800 °C (1,500 °F), making the fire extremely difficult to extinguish. Because of this high reactivity, Class D fires—which involve reactive metals like sodium and magnesium—require specialized dry-powder fire extinguishers rather than standard extinguishers that use carbon dioxide as a propellant or suppressing agent.12