Fossil fuels, coal, petroleum, and natural gas, which are derived from ancient organisms, necessarily contain organosulfur compounds, the removal of which is a major focus of oil refineries.
Fosilna goriva, ugalj, nafta, i prirodni gas, koji su izvedeni iz drevnih organizama, nužno sadrže organosumporna jedinjenja, i njihovo uklanjanje je u glavnom fokusu rafinerija nafte.