Decontamination chambers are areas on ships or bases that remove potentially harmful substances.
Usually using chemicals, radiation, or exotic energy fields, these devices are standard for exploration and some industrial applications. After the advent of Zerg infestation, Terran researchers have been ordered to constantly monitor mutations and update scanners to prevent losing high priority starships and space platforms. Up into the second Great War, current decon chambers can prevent most low level infections even if ships are at 40%. If more damages has accumulated, then the ships are considered lost. At this point, some commanders are forced to choose whether to keep on fighting or activate the Self-destruct.
Protoss decontamination chambers are much more advanced as they use psionic energy and force fields to isolate contaminants and purge them before anything reaches more sensitive components. The only recorded incidents where this technology has failed was when a hyper evolved parasite somehow hid in another organism during a rescue mission.