Section 250.805 - Hydrogen sulfide(a) In zones known to contain hydrogen sulfide (H2S) or in zones where the presence of H2S is unknown, as defined in § 250.490 , you must conduct production operations in accordance with that section and other relevant requirements of this subpart.(b) You must receive approval through the DWOP process (§§ 250.286 through 250.295 ) for production operations in HPHT environments known to contain H2S or in HPHT environments where the presence of H2S is unknown.