The answer is **Oil & Gas Refineries**. We don't really "mine" sulfur anymore. We capture it as waste to keep it out of the atmosphere (stopping acid rain). Ironically, this means the production of green technology is currently tethered to the production of fossil fuels. This is the **Green Paradox**: As we successfully decarbonize and shut down oil refineries, we are inadvertently cutting off the primary tap for the acid we need to build green tech. If we move too fast, we face a "sulfur crunch" that could stall battery production by 2030.