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• U.S. Environmental Protection Agency	13-P-0161

|	\ Office of Inspector General	February20 2013
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At a Glance
Why We Did This Review
We initiated this review to
determine whether the U.S.
Environmental Protection
Agency (EPA) has the data
needed to make key decisions
regarding air emissions from
oil and natural gas production.
Key decisions include the
need for regulations,
enforcement and permitting
decisions, and risk
assessment, among others.
Gas production in the United
States has grown significantly
in recent years. Between 1992
and 2010, about 210,000 new
gas wells were drilled. The
U.S. Department of Energy
projects that onshore crude oil
and natural gas production will
increase 30 and 18 percent,
respectively, from 2009 to
2025. The oil and gas
production sector and its
various production processes
emit large amounts of harmful
pollutants that impact air
quality on local, regional, and
global levels.
This report addresses the
following EPA Goal or
Cross-Cutting Strategy:
• Taking action on climate
change and improving air
quality.
For further information,
contact our Office of
Congressional and Public
Affairs at (202) 566-2391.
The full report is at:
www.epa.qov/oiq/reports/2013/
20130220-13-P-0161.pdf
EPA Needs to Improve Air Emissions Data for
the Oil and Natural Gas Production Sector
What We Found
High levels of growth in the oil and natural gas (gas) production sector, coupled with
harmful pollutants emitted, have underscored the need for EPA to gain a better
understanding of emissions and potential risks from the production of oil and gas.
However, EPA has limited directly-measured air emissions data for air toxics and
criteria pollutants for several important oil and gas production processes and
sources, including well completions and evaporative ponds. Also, EPA does not
have a comprehensive strategy for improving air emissions data for the oil and gas
production sector; the Agency did not anticipate the tremendous growth of the
sector, and previously only allocated limited resources to the issue.
In addition to their use in making a variety of key decisions, EPA uses air emissions
data to develop emission factors. These are representative values that relate the
quantity of a pollutant released with an activity associated with its release. States
use EPA's emission factors to develop emission inventories, issue permits for
facilities, and take enforcement actions. Limitations in EPA's air emissions data for a
number of oil and gas production pollutants have contributed to emission factors of
questionable quality. About half of EPA's Web Factor and Information Retrieval
System oil and gas production emission factors are rated below average or unrated
because they are based on insufficient or low quality data.
EPA uses its National Emissions Inventory (NEI) to assess risks, track trends, and
analyze envisioned regulatory controls. However, oil and gas production emissions
data in the 2008 NEI are incomplete for a number of key air pollutants. For example,
only nine states submitted criteria pollutant emissions data for small stationary
sources. Because so few states submitted data for this sector, we believe the NEI
likely underestimates oil and gas emissions. This hampers EPA's ability to
accurately assess risks and air quality impacts from oil and gas production activities.
Recommendations and Planned Agency Corrective Actions
We recommend that EPA develop and implement a comprehensive strategy for
improving air emissions data for the oil and gas production sector, prioritize which oil
and gas production emission factors need to be improved, develop additional
emission factors as appropriate, and ensure the NEI data for this industry sector are
complete. EPA concurred with our recommendations to develop a comprehensive
strategy, improve and prioritize emission factors, and develop default nonpoint
emission estimates. The Agency did not concur with our recommendations to ensure
that states submit required data and develop default calculation guidance. These
recommendations are unresolved pending the Agency's final report response.
Noteworthy Achievements
EPA is conducting field studies to develop new methods to measure emissions and
investing in a new Emissions Inventory System.

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