Carbon dioxide tank

A carbon dioxide tank was a physical storage device on board 22nd century Starfleet vessels which contained a gas capable of rendering Humans unconscious. The tanks could be connected to a ship's central ventilation by rerouting the transfer lines via the atmospheric recycling manifold.

In 2152, Doctor Phlox was forced to use the manifold to access the 's carbon dioxide tanks and distribute the gas throughout the ship, in order to evict a series of non-corporeal lifeforms called "Wisps" from the bodies of crewmembers who had been taken over by the aliens.