Gasi rechisikigo, iro "rinopa simba remabhuroko" rinokosha, rinowanzova nehydrogen sulfide (H₂S) uye organic sulfur compounds (mercaptans, COS), izvo zvine chepfu, zvinoparadza, uye zvinogadzira SOx inokuvadza kana yatsva. Saka, kubvisa sulfurization (kunakisa) kwakakosha.