Air Emission Control Requirements

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Analysis of States’ and EPA Oil & Gas Air Emissions Control Requirements for Selected Basins in the Western United States
(2013 Update):
(PDF: 4 MB) (DOC: 5MB) (11/8/13)

The primary intent of this analysis is to examine the effect that two recent federal air quality actions might have on the air pollution emissions from the oil and natural gas (O&G) industry exploration and production sector in the WRAP region of the western United States.

The first of the two recent federal actions considered here is a Federal Implementation Plan (FIP) known as “Review of New Sources and Modifications in Indian Country. The second federal action considered here is the issuance of a suite of four air regulations for the oil and natural gas industry: 1) a New Source Performance Standard (NSPS Subpart OOOO) for VOCs; 2) a New Source Performance Standard (NSPS Subpart OOOO) for sulfur dioxide; 3) a National Emissions Standard for Hazardous Air Pollutants (NESHAP Subpart HH) for oil and natural gas production; and 4) a National Emissions Standard for Hazardous Air Pollutants (NESHAP Subpart HHH) for natural gas transmission and storage.

The NSPS/NESHAP regulations focus on VOCs, but EPA has had other NSPS in place for a number of years which focus on control of combustion emissions. These NSPS include Subpart Db and Dc for boilers, Subpart IIII for stationary compression ignition (diesel) engines, Subpart JJJJ for stationary spark ignition engines and Subpart KKKK for stationary combustion turbines. NOx is a major pollutant from these four source categories.

NOx is also emitted in large quantities from temporary engines in the fields that power such equipment as drill and workover rigs. Since these engines generally operate for some period of time less than a year at any one site before being relocated, EPA regulates these temporary engines as “Nonroad Mobile” sources. So in addition to looking at the VOC impact of the recent federal O&G actions, this analysis also examines the impact of previously existing federal rules on the NOx component of the inventories.

Finally this document describes the most current WRAP effort at evaluating O&G operations, which is a BLM Sponsored emission inventory compilation for the Montana Great Plains and Williston Basins. This effort will produce a 2011 year baseline emission inventory, along with projections 5-7 years into the future.

This analysis uses data from the WRAP-Western Energy Alliance Phase III O&G Emission Inventory project (details posted at These Phase III O&G emission totals reflected O&G control rules in place in the states at the time those inventories were compiled. Some of the state regulations may have been updated since that time.

The WRAP produced an initial copy of this analysis on November 28, 2011 (w/ January 8, 2012 Errata Corrections). Since that time EPA has finalized the O&G NSPS and new information has been gleaned from the states on some of their O&G control programs. Thus this current 2013 document provides an update to that initial 2011 report addressing the changes that have occurred since 2011.