Sulfur is the world's highest-volume byproduct commodity: almost all commercial supply (85 Mt/yr globally in 2024) is recovered involuntarily during oil refining, natural gas sweetening, coking, and metal smelting, rather than intentionally mined. This structural reality makes sulfur unique among high-volume industrial elements — supply is tethered to fossil fuel processing rates, not to sulfur demand, and no economically viable alternative source exists. USGS reports no quantitative economic reserves by country; the concept of sulfur "reserves" is subsumed by oil, gas, and metal sulfide ore reserves. World resources in elemental form total approximately 5 billion metric tons (evaporite, volcanic, petroleum, gas, tar sands, and metal sulfides), with far larger amounts in gypsum, anhydrite, coal, and organic shale where extraction is currently uneconomic.

About 90% of all sulfur consumed is converted to sulfuric acid, and the single largest downstream use is phosphate fertilizer production — the link that connects fossil fuel infrastructure to global food supply. China dominates world production at 22%, with Russia, Saudi Arabia, UAE, Kazakhstan, and Canada each supplying 6–9%. The United States is modestly import-reliant (7% net import reliance in 2024), sourcing ~70% of its imported sulfur from Canada. US production fell 5% in 2024 to 8.2 Mt, driven by a 6% decline at petroleum refineries and natural gas plants. Price volatility is a structural feature: the 5-year range spans $24.90/t (2020) to $177.80/t (2022), with swings driven by phosphate fertilizer demand cycles rather than supply constraints. In 2024, average unit value was $50/t while Tampa contract prices swung from $69 to $116/long ton within a single year.

Looking forward, two opposing forces shape sulfur's supply-demand balance. On the supply side, Middle Eastern refinery expansions will add byproduct sulfur from 2025 onward, and the long-run energy transition gradually reduces fossil fuel throughput — implying eventual structural tightening of recovered sulfur supply. On the demand side, high-pressure acid leach (HPAL) nickel processing for battery materials is a growing new sulfur consumer, and phosphate fertilizer demand in Africa and west Asia is expanding. The substitutes picture is stark: USGS notes "substitutes for sulfur at present or anticipated price levels are not satisfactory," particularly for fertilizer applications.