Explosive decompression was the process where a being exposed to an unpressurized environment—usually when exposed to a vacuum—was rapidly crushed from an increase in pressure, and died. Skakoans wore a special suit to prevent this as they were unable to survive in most environments. If this suit was ruptured, the Skakoan in question would instantly die.
Explosive decompression also occurred to starships traveling through hyperspace. The physics in hyperspace were unpredictable, and whereas a ship's hull typically exploded outward, a breached part of a ship could simply leave it in a seismic tug, eventually exiting hyperspace and reverting to realspace. When the Harbinger collided with the Omen just as the latter entered hyperspace in 5000 BBY, the Omens armory and a part of its quarterdeck was torn away from the Sith dreadnaught by a seismic tug.
When Jedi Luke Skywalker and Leia Organa Solo crashed their ScragHull commando boat into the Ormni asteroid crusher, the pair narrowly escaped the explosion of their starfighter's fusion core along with R2-D2 by locking themselves in a locker room aboard the Ormni, albeit with severe injuries. The Ormnis Captain was certain that there were no survivors, given that the pilots of the ScragHull would have had to endure the explosion of a fusion core and the resulting explosive decompression of the vault that they crashed into; however, the Sith Vestara Khai asserted that it was possible for pilots to survive such an ordeal.