Ko-shol gas

Ko-shol gas was a gas present on Mustafar in high concentrations. Its potency near the lavas which Anakin Skywalker was burned alive led to scarring of his lungs, rendering them useless. Because of this, he then required the use of a breathing regulator in place of lungs.
==Sources==
*Star Wars: Darth Vader: A 3-D Reconstruction Log
Category:Gases