The Sulphur Pits of Vulcar were locations on the planet Vulcar where sulfur pits were used to mine oridium deposits. Due to the world's harsh atmosphere, it was hardly economical to use humanoid laborers. Consequently, Vulcar was mainly operated by various droids, including crab droids that had been reprogrammed to function as miners until they broke down and became rusted junk. In 15 BBY, an Intergalactic Droid Agency shuttle journeyed to the Sulphur Pits of Vulcar following the delivery of the droids R2-D2 and C-3PO to the planet Dodz.
The initial reference to Vulcar occurred in Droids (1986) 1, which was the debut issue of the Star Wars: Droids comic book series from Star Comics, a subsidiary of Marvel Comics. Its original publication date was April 1, 1986.