Standards of Performance for Onshore Natural Gas Processing: SO2 Emissions (40 CFR 60 Subpart LLL, Subpart OOOO and Subpart OOOOa)

Applicability to land based crude oil and natural gas extraction and production industry

Applies to sweetening units located on land which process natural gas produced from either onshore or offshore wells. The provisions of this subpart are applicable to the following types of affected facilities that process natural gas: each sweetening unit, and each sweetening unit followed by a sulfur recovery unit. Facilities that have a design capacity less than 2 long tons per day (LT/D) of hydrogen sulfide (H2S) in the acid gas (expressed as sulfur) are required to comply with certain recordkeeping provisions at Section 60.647(c) but are not required to comply with substantive standards at Sections 60.642 through 60.646.

Note: The provisions of these subparts do not apply to sweetening facilities producing acid gas that is completely reinjected into oil-or-gas-bearing geologic strata or that is otherwise not released to the atmosphere.

Depending when the sweetening unit was constructed, reconstructed or modified, different subparts may apply:

Construction, reconstruction or modification date


On or before August 23, 2011

40 CFR Part 60 Subpart LLL

After August 23, 2011, and on or before September 18, 2015

40 CFR Part 60 Subpart OOOO

After September 18, 2015

40 CFR Part 60 Subpart OOOOa

Compliance information

Compliance Dates: Affected facilities must comply upon promulgation of the subpart or upon startup, whichever is later.

More information

40 CFR Part 60 Subpart OOOO. Oil and Natural Gas Sector: New Source Performance Standards and National Emission Standards for Hazardous Air Pollutant Reviews.

Compliance Monitoring. New Source Performance Standards and State Implementation Plans.