Phaser coolant
Phaser coolant was a substance used to prevent shipboard phasers from overheating. It came in the form of a toxic gas, and prolonged exposure to it could be fatal.

In 2266, the phaser coolant seal on the  was breached due to damage caused by an attacking Romulan Bird-of-Prey, causing coolant to fill the phaser control room. Both crewmembers manning the phasers, Lieutenants Tomlinson and , were rendered unconscious by the fumes. Although Stiles was saved by Spock, Tomlinson died as a result of his exposure. ()

de:Phaserkühlung
Materials
Weapon components