In the 1960s, an American company set up a mining community in the Dallol region in order to mine the mineral, potash. It is in the nature of Americans that they hear a place described as an "uninhabitable, volcanic, wasteland" and feel they can just come in and show the locals how it's done. After a couple of years of trying to mine what is basically the lava planet from Revenge of the Sith, the contractors came to the conclusion that potash, an ingredient for goddamn fertilizer, was probably easier to come by in the world.
"Hey Hank, this is fun and all but I was thinking maybe, you know, fuck it. How do you feel about that?"
The local Afar people, on the other hand, have lived and worked here for thousands of years, and through the blistering heat and ridiculously harsh conditions they've adapted to become some of the most badass people on the planet. They make a living hacking at the ground with giant axes all day long in order to backbreakingly liberate tons of one particularly valuable resource... table salt.
Yes, that's where it comes from.