Where this text comes from
- Citation
- 40 CFR Part 98, Subpart W
- Official title
- Subpart W—Petroleum and Natural Gas Systems
- Text as of
- eCFR current through 2026-10-28, retrieved 2026-10-30
- Latest amendment
- 2025-01-01
- Source note
- 75 FR 74488, Nov. 30, 2010, unless otherwise noted.
Headings and quoted sections on this page are copied from the eCFR text of Subpart W without changes. AirPermitHub checks eCFR every week and reviews any change before publishing it, so this page can trail eCFR by a few days. eCFR is maintained by the Office of the Federal Register and the Government Publishing Office. It is not an official legal edition of the CFR, and it does not show how an agency has applied the rule in a permit.
Where to look in Subpart W
Sections sorted by the words in their eCFR headings. Read the full section before relying on it; requirements often sit in more than one place.
Who the subpart covers, in the rule's own words
The sections that set out what the subpart applies to, quoted in full from eCFR. Dates, sizes, and other figures are the rule's, not AirPermitHub's.
§ 98.230 Definition of the source category.
Open in eCFR(a) This source category consists of the following industry segments:
(1) Offshore petroleum and natural gas production. Offshore petroleum and natural gas production is any platform structure, affixed temporarily or permanently to offshore submerged lands, that houses equipment to extract hydrocarbons from the ocean or lake floor and that processes and/or transfers such hydrocarbons to storage, transport vessels, or onshore. In addition, offshore production includes secondary platform structures connected to the platform structure via walkways, storage tanks associated with the platform structure and floating production and storage offloading equipment (FPSO). This source category does not include reporting of emissions from offshore drilling and exploration that is not conducted on production platforms.
(2) Onshore petroleum and natural gas production. Onshore petroleum and natural gas production means all equipment on a single well-pad or associated with a single well-pad (including but not limited to compressors, generators, dehydrators, storage vessels, engines, boilers, heaters, flares, separation and processing equipment, and portable non-self-propelled equipment, which includes well drilling and completion equipment, workover equipment, and leased, rented or contracted equipment) used in the production, extraction, recovery, lifting, stabilization, separation or treating of petroleum and/or natural gas (including condensate). This equipment also includes associated storage or measurement vessels, all petroleum and natural gas production equipment located on islands, artificial islands, or structures connected by a causeway to land, an island, or an artificial island. Onshore petroleum and natural gas production also means all equipment on or associated with a single enhanced oil recovery (EOR) well-pad using CO2 or natural gas injection.
(3) Onshore natural gas processing. Onshore natural gas processing means the forced extraction of natural gas liquids (NGLs) from field gas, fractionation of mixed NGLs to natural gas products, or both. Natural gas processing does not include a Joule-Thomson valve, a dew point depression valve, or an isolated or standalone Joule-Thomson skid. This segment also includes all residue gas compression equipment owned or operated by the natural gas processing plant.
(4) Onshore natural gas transmission compression. Onshore natural gas transmission compression means any stationary combination of compressors that move natural gas from production fields, natural gas processing plants, or other transmission compressors through transmission pipelines to natural gas distribution pipelines, LNG storage facilities, or into underground storage. In addition, a transmission compressor station includes equipment for liquids separation, and tanks for the storage of water and hydrocarbon liquids. Residue (sales) gas compression that is part of onshore natural gas processing plants are included in the onshore natural gas processing segment and are excluded from this segment.
(5) Underground natural gas storage. Underground natural gas storage means subsurface storage, including depleted gas or oil reservoirs and salt dome caverns that store natural gas that has been transferred from its original location for the primary purpose of load balancing (the process of equalizing the receipt and delivery of natural gas); natural gas underground storage processes and operations (including compression, dehydration and flow measurement, and excluding transmission pipelines); and all the wellheads connected to the compression units located at the facility that inject and recover natural gas into and from the underground reservoirs.
(6) Liquefied natural gas (LNG) storage. LNG storage means onshore LNG storage vessels located above ground, equipment for liquefying natural gas, compressors to capture and re-liquefy boil-off-gas, re-condensers, and vaporization units for re-gasification of the liquefied natural gas.
(7) LNG import and export equipment. LNG import equipment means all onshore or offshore equipment that receives imported LNG via ocean transport, stores LNG, re-gasifies LNG, and delivers re-gasified natural gas to a natural gas transmission or distribution system. LNG export equipment means all onshore or offshore equipment that receives natural gas, liquefies natural gas, stores LNG, and transfers the LNG via ocean transportation to any location, including locations in the United States.
Show the rest of § 98.230 (4 more paragraphs)Hide the rest of § 98.230
(8) Natural gas distribution. Natural gas distribution means the distribution pipelines and metering and regulating equipment at metering-regulating stations that are operated by a Local Distribution Company (LDC) within a single state that is regulated as a separate operating company by a public utility commission or that is operated as an independent municipally-owned distribution system. This segment also excludes customer meters and regulators, infrastructure, and pipelines (both interstate and intrastate) delivering natural gas directly to major industrial users and farm taps upstream of the local distribution company inlet.
(9) Onshore petroleum and natural gas gathering and boosting. Onshore petroleum and natural gas gathering and boosting means gathering pipelines and other equipment used to collect petroleum and/or natural gas from onshore production gas or oil wells and used to compress, dehydrate, sweeten, or transport the petroleum and/or natural gas to a downstream endpoint, typically a natural gas processing facility, a natural gas transmission pipeline or a natural gas distribution pipeline. Gathering and boosting equipment includes, but is not limited to gathering pipelines, separators, compressors, acid gas removal units, dehydrators, pneumatic devices/pumps, storage vessels, engines, boilers, heaters, and flares. Gathering and boosting equipment does not include equipment reported under any other industry segment defined in this section. Gathering pipelines operating on a vacuum and gathering pipelines with a GOR less than 300 standard cubic feet per stock tank barrel (scf/STB) are not included in this industry segment (oil here refers to hydrocarbon liquids of all API gravities).
(10) Onshore natural gas transmission pipeline. Onshore natural gas transmission pipeline means all natural gas transmission pipelines as defined in § 98.238.
(b) [Reserved]
[75 FR 74488, Nov. 30, 2010, as amended at 76 FR 80574, Dec. 23, 2011; 79 FR 70385, Nov. 25, 2014; 80 FR 64283, Oct. 22, 2015; 89 FR 42221, May 14, 2024]
§ 98.231 Reporting threshold.
Open in eCFR(a) You must report GHG emissions under this subpart if your facility contains petroleum and natural gas systems and the facility meets the requirements of § 98.2(a)(2), except for the industry segments in paragraphs (a)(1) through (4) of this section.
(1) Facilities must report emissions from the onshore petroleum and natural gas production industry segment only if emission sources specified in § 98.232(c) emit 25,000 metric tons of CO2 equivalent or more per year.
(2) Facilities must report emissions from the natural gas distribution industry segment only if emission sources specified in § 98.232(i) emit 25,000 metric tons of CO2 equivalent or more per year.
(3) Facilities must report emissions from the onshore petroleum and natural gas gathering and boosting industry segment only if emission sources specified in § 98.232(j) emit 25,000 metric tons of CO2 equivalent or more per year.
(4) Facilities must report emissions from the onshore natural gas transmission pipeline industry segment only if emission sources specified in § 98.232(m) emit 25,000 metric tons of CO2 equivalent or more per year.
(b) For applying the threshold defined in § 98.2(a)(2), natural gas processing facilities must also include owned or operated residue gas compression equipment.
[75 FR 74488, Nov. 30, 2010, as amended at 80 FR 64284, Oct. 22, 2015]
Every section in Subpart W
9 sections and 7 tables, in eCFR order. Each link opens the official text.
- § 98.230Definition of the source category.Amended 2025-01-01
- § 98.231Reporting threshold.Amended 2017-01-01
- § 98.232GHGs to report.Amended 2025-01-01
- § 98.233Calculating GHG emissions.Amended 2025-01-01
- § 98.234Monitoring and QA/QC requirements.Amended 2025-01-01
- § 98.235Procedures for estimating missing data.Amended 2025-01-01
- § 98.236Data reporting requirements.Amended 2025-01-01
- § 98.237Records that must be retained.Amended 2025-01-01
- § 98.238Definitions.Amended 2025-01-01
Tables and appendices
- TableTable W-1 to Subpart W of Part 98—Default Whole Gas Population Emission FactorsSee eCFR
- TableTable W-2 to Subpart W of Part 98—Default Whole Gas Leaker Emission FactorsSee eCFR
- TableTable W-3 to Subpart W of Part 98—Default Total Hydrocarbon Population Emission FactorsSee eCFR
- TableTable W-4 to Subpart W of Part 98—Default Total Hydrocarbon Leaker Emission FactorsSee eCFR
- TableTable W-5 to Subpart W of Part 98—Default Methane Population Emission FactorsSee eCFR
- TableTable W-6 to Subpart W of Part 98—Default Methane Leaker Emission FactorsSee eCFR
- TableTable W-7 to Subpart W of Part 98—Default Methane Emission Factors for Internal Combustion EquipmentSee eCFR
Amendment history
Dates on which eCFR records a change to any section of Subpart W, newest first.
- 2025-01-01
- 2024-10-04
- 2024-09-04
- 2024-08-28
- 2024-07-15
- 2024-05-14
- 2019-11-01
- 2019-09-19
- 2019-01-01
- 2017-01-01
To read the rulemakings behind these dates, search the Federal Register for Subpart W. New EPA air rules and proposals also appear in the Federal Air Rule Tracker.
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