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U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF INSPECTOR GENERAL
Hotline Report:
Improving air quality
EPA Did Not Use Allegedly
Flawed Studies to Estimate
Methane Emissions or Set
New Source Performance
Standards for Oil and Natural
Gas Production
Report No. 18-P-0129
March 16, 2018
-------
Report Contributors: Richard Jones
Jim Hatfield
Erica Hauck
Alicia Mariscal
Abbreviations
C02e
Carbon Dioxide Equivalent
EDF
Environmental Defense Fund
EPA
U.S. Environmental Protection Agency
IPAA
Independent Petroleum Association of America
IPCC
Intergovernmental Panel on Climate Change
OIG
Office of Inspector General
UNFCCC
United Nations Framework Convention on Climate Change
UT-Austin
University of Texas-Austin
Cover photo: An oil production site in North Dakota. (EPA photo)
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* — * U.S. Environmental Protection Agency 18-P-0129
March 16, 2018
. u.o. tiiviiuiiiiitriiidi riuicuu
\ Office of Inspector General
At a Glance
Why We Did This Review
The U.S. Environmental
Protection Agency's (EPA's)
Office of the Inspector General
conducted this review in
response to a hotline complaint
alleging that the EPA used
results from two flawed studies
to estimate methane emissions
and make policy decisions
regarding oil and natural gas
production. The complaint
alleged that two methane
emissions studies conducted by
the University of Texas-Austin
(UT-Austin), and sponsored by
the Environmental Defense
Fund (EDF), were flawed due
to a malfunction in one of the
measurement devices called
a Hi Flow Sampler.
Our objectives were to
determine (1) how the EPA
estimates methane emissions
from oil and natural gas
production, including whether
the EPA used results from the
two EDF/UT-Austin studies
to estimate emissions; and
(2) whether concerns about
technical or other problems with
the studies were identified or
brought to the EPA's attention,
and how the EPA addressed
and resolved those concerns.
EPA Did Not Use Allegedly Flawed Studies to Estimate
Methane Emissions or Set New Source Performance
Standards for Oil and Natural Gas Production
Methane is a potent
greenhouse gas
emitted from natural
and industrial sources,
including oil and natural
gas production facilities.
What We Found
The Inventory of U.S. Greenhouse Gas Emissions
and Sinks (Greenhouse Gas Inventory) reflects the
EPA's official nationwide estimate for greenhouse
gas emissions from all man-made sources,
including those from oil and natural gas production.
The inventory is developed using a variety of data
sources and emission estimation methodogies.
One source of data for the inventory is emissions and activity data reported to the
EPA under its Greenhouse Gas Reporting Program. This reporting program
requires large emission sources and fuel suppliers to calculate and report their
greenhouse gas emissions data to the EPA.
The EPA used its Greenhouse Gas Inventory development process to consider
information related to the EDF/UT-Austin studies and the Hi Flow Sampler. In
memorandums issued in 2015 and 2016, inventory staff requested expert and
public feedback on specific aspects of the EDF/UT-Austin studies, how data could
potentially be used for the inventory, and potential problems with the Hi Flow
Sampler.
The EPA ultimately did not make any methodological revisions to the Greenhouse
Gas Inventory or to the Greenhouse Gas Reporting Program based on the
EDF/UT-Austin studies, and data from the studies have not been incorporated into
the inventory. In addition, the EPA did not use any data from the EDF/UT-Austin
studies to set the final 2016 New Source Performance Standards to limit methane
emissions from the oil and natural gas industry.
We make no recommendations.
This report addresses the
following:
• Improving air quality.
Send all inquiries to our public
affairs office at (202) 566-2391
or visit www.epa.gov/oiq.
Listing of OIG reports.
-------
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
THE INSPECTOR GENERAL
March 16, 2018
MEMORANDUM
SUBJECT: EPA Did Not Use Allegedly Flawed Studies to Estimate Methane Emissions or
Set New Source Performance Standards for Oil and Natural Gas Production
Report No. 18-P-0129
This is our report on the subject evaluation conducted by the Office of Inspector General (OIG)
of the U.S. Environmental Protection Agency (EPA). The project number for this evaluation was
OPE-FY17-0017. This report represents the opinion of the OIG and does not necessarily represent the
final EPA position.
This report contains no recommendations, and you are not required to respond to this report. However,
if you submit a response, it will be posted on the OIG's public website, along with our memorandum
commenting on your response. Your response should be provided as an Adobe PDF file that complies
with the accessibility requirements of Section 508 of the Rehabilitation Act of 1973, as amended. The
final response should not contain data that you do not want to be released to the public; if your response
contains such data, you should identify the data for redaction or removal along with corresponding
justification.
We will post this report to our website at www.epa.gov/oig.
FROM: Arthur J. Elkins Jr.
TO:
Bill Wehrum, Assistant Administrator
Office of Air and Radiation
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EPA Did Not Use Allegedly Flawed Studies to Estimate
Methane Emissions or Set New Source Performance
Standards for Oil and Natural Gas Production
18-P-0129
Table of C
Purpose 1
Background 1
Responsible Office 4
Scope and Methodology 4
Results 6
Conclusion 13
Agency Response and OIG Evaluation 13
Appendix
A Distribution 14
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Purpose
In response to a hotline complaint, the U.S. Environmental Protection Agency's
(EPA's) Office of Inspector General (OIG) conducted this review to determine
the following:
(1) How the EPA estimates methane emissions from the oil and natural gas
production sector, including the extent to which the EPA has used results
from the 2013 and 2014 emission studies conducted jointly by the
Environmental Defense Fund (EDF) and the University of Texas-Austin
(UT-Austin) to estimate those emissions.1
(2) Whether concerns about technical or other problems with the studies were
identified or brought to the EPA's attention, and how the EPA addressed
and resolved those concerns.
Background
In 2016, the OIG received a hotline complaint alleging that two methane emission
studies conducted by EDF/UT-Austin in 2013 and 2014 were flawed, and that the
EPA had made greenhouse gas policy and emission estimation decisions based on
the studies. The complaint alleged that the results of the studies were flawed
because one of the sampling devices (called a Hi Flow Sampler) used to measure
emissions for some of the sources malfunctioned, particularly when measuring
gas streams that contained high amounts of hydrocarbons in addition to methane.
The complaint alleged that the malfunction caused the EDF/UT-Austin studies
to underestimate emissions. In addition, the complaint alleged that the Hi Flow
Sampler can malfunction when measuring high methane gas streams, such as
those found in the transmission segment of the industry. The Hi Flow Sampler is
a high-volume sampler, which is a type of measurement device approved by the
EPA for measuring and reporting methane emissions from certain sources in the
transmission and processing segments, but not the production segment.
Methane Emissions From the Oil and Natural Gas Production Sector
Methane is the second-most emitted greenhouse gas and has a heat trapping
potential of up to 25 times that of carbon dioxide. According to the EPA, about
one-third of U.S. methane emissions come from natural gas and petroleum
1 Allen, D.T., V.M. Torres, J. Thomas, D. Sullivan, M. Harrison, A. Hendler et al., 2013. Measurements of Methane
Emissions at Natural Gas Production Sites in the United States. Proc. Natl. Acad. Sci. USA 110:17768-17773.
Allen, D.T., A. Pacsi, D. Sullivan, D. Zavala-Araiza, M. Harrison, K. Keen et al., 2014. Methane Emissions from
Process Equipment at Natural Gas Production Sites in the United States: Pneumatic Controllers. Environ. Sci.
Technol. 49:633-640.
18-P-0129
1
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systems.2 While methane emissions
from other segments of the natural
gas industry (e.g., distribution,
transmission and storage, and
processing) decreased between
1990 and 2015, the EPA estimates
that emissions from the production
segment increased by 51 percent
(Figure 1). Oil and natural gas
production in the U.S. is rapidly
expanding due, in part, to exploration
of large unconventional gas reserves.
The Energy Information
Administration at the U.S.
Department of Energy projects
that natural gas production
in the U.S. will increase by
45 percent between 2013 and 2040.
The process of oil and natural gas production consists of wells used to extract oil
and natural gas from underground formations. Emissions are released from the
wells, and from well-site gas treatment equipment such as dehydrators and
separators. In total, the Energy Information Administration estimates there were
over 1 million producing oil and natural gas wells nationwide in 2016.
Published research on estimates of methane emissions from natural gas
production have varied widely, and a great amount of uncertainty exists in
estimating these emissions. For example, studies using top-down approaches,
such as ground monitors or aircraft that measure ambient concentrations of
methane, indicate that traditional approaches used to develop emission inventories
may be significantly underestimating emissions.
Environmental Defense Fund Studies on Emissions From Oil and
Natural Gas Production
Given the uncertainties with methane emission estimation and measurement in the
natural gas industry, the EDF collaborated with about 100 research institutions,
universities and companies to conduct a series of 16 emission studies covering
all segments of the industry. Two of these studies focused on the production
segment. Dr. David T. Allen, former chair of the EPA's Science Advisory Board,
led both studies at UT-Austin.
Figure 1: EPA estimated methane emissions
trends comparison for the natural gas industry
(1990-2015)
Methane
emissions
from production
segment:
Methane
51% Increase
emissions
from other
segments:
L
55% Decrease
L
Source: OIG image derived from EPA data.
2 Petroleum systems, as defined by the EPA, include oil production, as well as oil transportation and petroleum
refining. Approximately 98 percent of total methane emissions from petroleum systems come from oil production.
18-P-0129
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The first production segment study, which was published in 2013,3 involved
direct measurements of well-site processes and equipment using several different
methods, including the Hi Flow Sampler device. The second production segment
study, which was published in 2014,4 involved direct measurements of pneumati c
controllers used to regulate routine functions at well sites. This study also used a
Hi Flow Sampler to measure emissions for a small percentage of the controllers in
the study.
Hi Flow Sampler
The Hi Flow Sampler is a portable instrument
designed to capture and quantify leaks at natural
gas transmission, storage and compressor
facilities, where gas streams are generally
comprised almost entirely of methane. Under
Subpart W of the EPA's Greenhouse Gas
Reporting Program, high-volume samplers, such
as the Hi Flow Sampler, are approved for directly
measuring methane emissions from three sources
(storage tanks, centrifugal compressor venting,
and reciprocating compressor venting) in the
processing and transmission segments. Direct
measurement using these devices is one option,
among several, that facilities can use to estimate
and report emissions for these sources.
Use of high-volume samplers is not an approved method for any source in the
production segment. Further, the manufacturer of the Hi Flow Sampler did not
intend for it to be used at production facilities where gas streams can include a
high amount of non-methane hydrocarbons. However, researchers have begun
using the Hi Flow Sampler device for studies on the production segment, such as
the EDF/UT-Austin studies, because the device is the most convenient and cost-
effective way to capture and quantify an entire leak.
i
A pneumatic controller at a
production site in Utah.
(EPA photo)
3 Allen, D.T., V.M. Torres, J. Thomas, D. Sullivan, M. Harrison, A. Hendleret al., 2013. Measurements of 'Methane
Emissions at Natural Gas Production Sites in the United States. Proc. Natl. Acad. Sci. USA 110:17768-17773.
4 Allen, D.T., A. Pacsi. D. Sullivan, D. Zavala-Araiza, M. Harrison. K. Keen et al., 2014. Methane Emissions from
Process Equipment at Natural Gas Production Sites in the United States: Pneumatic Controllers. Environ. Sci.
Technol. 49:633-640.
18-P-0129
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EPA's New Source Performance Standards for Oil and Gas
Production
In 2016, the EPA updated its New Source Performance Standards5 for the oil and
natural gas industry to reduce methane emissions. These were the first standards
to specifically regulate methane emissions from the industry. The prior standards
issued in 2012 were expected to result in methane reductions as a co-benefit of
reducing other pollutants, but they did not set specific standards for methane
emissions. The 2016 standards have built on the 2012 standards to set specific
standards to reduce methane emissions from the oil and natural gas industry,
including production sources such as well completions, pneumatic controllers,
and fugitive emissions.
Responsible Office
The EPA's Office of Air and Radiation, Office of Atmospheric Programs, is
responsible for estimating methane emissions from oil and natural gas production.
Scope and Methodology
We conducted our review from July 2017 to January 2018. We conducted this
performance audit in accordance with generally accepted government auditing
standards. Those standards require that we plan and perform the audit to obtain
sufficient, appropriate evidence to provide a reasonable basis for our findings and
conclusions based on our objectives. We believe that the evidence obtained
provides a reasonable basis for our findings and conclusions based on our
objectives.
To address our objectives, we reviewed regulations, policies, procedures and
guidance related to evaluating methane emissions from oil and natural gas
production. We placed particular emphasis on criteria and quality assurance
processes for greenhouse gas reporting, the development of the Inventory of U.S.
Greenhouse Gas Emissions and Sinks, and procedures for revising methods to
estimate emissions in the inventory and under Subpart W of the Greenhouse Gas
Reporting Program.
5 Section 111 of the Clean Air Act authorizes the EPA to develop technology-based air emission standards for
specific categories of stationary sources. These standards apply to newly constructed, modified and reconstructed
sources, and are referred to as the New Source Performance Standards. The EPA can delegate implementation and
enforcement of the standards to the states. However, even when delegated to the states, the EPA retains authority to
enforce the standards.
18-P-0129
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We reviewed the 2013 and 2014 EDF/UT-Austin studies, as well as critiques of
the studies published by engineer Touche Howard.6 We also reviewed published
articles by Mr. Howard regarding the potential failure of the Hi Flow Sampler
under certain circumstances. We interviewed Dr. David Allen and the researcher
who oversaw the measurements for the studies, Mr. Howard, and representatives
from the manufacturer and distributor of the Hi Flow Sampler.
To determine whether the EPA used data from the 2013 and 2014
EDF/UT-Austin studies to develop methane emissions estimates, we reviewed
recent Greenhouse Gas Inventory reports and supporting documentation,
including memorandums that inventory staff issued soliciting feedback on
new data and methods for the inventory. In addition, we reviewed supporting
documentation for the EPA's 2016 oil and natural gas New Source Performance
Standards. We also reviewed internal EPA communications about the 2013 and
2014 studies, and the potential problems with the Hi Flow Sampler.
We interviewed staff from two Office of Air and Radiation offices: the Office of
Atmospheric Programs, and the Office of Air Quality Planning and Standards.
Staff from the EPA's Office of Research and Development and EPA Region 8
were also interviewed.
We also met with representatives from the Independent Petroleum Association of
America (IPAA) after receiving written concerns from that organization about the
EPA's development of emission estimates. The IPAA expressed concerns that the
EPA was overestimating methane emissions in its Greenhouse Gas Inventory, and
had overestimated emissions for certain types of facilities when developing the
2016 New Source Performance Standards for oil and natural gas production sites.
Since the EPA plans to reconsider these standards for oil and natural gas
production, we did not review IPAA's concern about the New Source
Performance Standards.
We conducted limited work to assess the topic areas of IPAA's concerns about
overestimation of methane emissions in the Greenhouse Gas Inventory,7 since
those concerns were not within our scope. Based on our review of inventory
documents, we concluded that the EPA followed its normal development process
in relation to those topic areas. As a result, we did not review them further.
6 Touche Howard is an engineer who developed a high-flow sampling device in the early 1990s. In the early 2000s,
Mr. Howard's concept was commercialized by a private company with different hardware and components and
named the Hi Flow Sampler.
7 IPAA's concerns involved the revised methods that the EPA used in the 1990-2014 Greenhouse Gas Inventory to
(1) extrapolate, or scale, data from facilities that reported to the Greenhouse Gas Reporting Program to facilities that
are not required to report to the program; and (2) estimate the number of gathering and boosting facilities and
associated emissions.
18-P-0129
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Results
The EPA has two established programs that estimate U.S. greenhouse gas
emissions, including methane emissions from oil and natural gas production:
• The Greenhouse Gas Reporting Program.
• The Inventory of U.S. Greenhouse Gas Emissions and Sinks.
We found that the EPA used the Greenhouse Gas Inventory development process
to consider and solicit feedback on the EDF/UT-Austin studies and the Hi Flow
Sampler. However, the EPA has not used data or conclusions from the studies to
revise its methane emission estimates for oil and gas production, or to set New
Source Performance Standards to limit methane emissions from the industry.
Greenhouse Gas Reporting Program
The 2008 Consolidated Appropriations Act required the EPA to develop a rule
that mandates the reporting of greenhouse gases. The implementation of this rule
is referred to as the Greenhouse Gas Reporting Program, which requires large
emission sources and fuel suppliers to report their greenhouse gas emissions data
to the EPA. The program has a reporting threshold of 25,000 metric tons of
carbon dioxide equivalent (CChe) per year, so only those oil and natural gas
production facilities exceeding that threshold are required to report emissions
under the program.8
The Greenhouse Gas Reporting Program does not reflect all emissions from the
industry. Subpart W of the program contains specific reporting requirements for
oil and natural gas production sources, including methods to be used by facilities
to estimate emissions from specific sources. For production, many of the methods
are engineering calculations that incorporate "emission factors."9 Figure 2
provides an overview of the petroleum and natural gas industry, and the
operations covered by the Greenhouse Gas Reporting Program.
8 In general, a "facility" for purposes of the Greenhouse Gas Reporting Program means all co-located emission
sources that are commonly owned or operated. However, the program has developed a specialized facility definition
for certain segments, including onshore production. For onshore production, a "facility" includes all emissions
associated with wells owned or operated by a single company in a specific hydrocarbon producing basin (as defined
by the geologic provinces published by the American Association of Petroleum Geologists).
9 The EPA defines an emission factor as a representative value that attempts to relate the quantity of a pollutant
released to the atmosphere with an activity associated with the release of that pollutant.
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Figure 2: Oil and natural gas operations covered by the Greenhouse Gas Reporting
Program
Production & Processing Natural Gas Transmission & Storage
1. Onshore Petroleum & Natural Gas
Production
2. Offshore Petroleum & Natural Gas
Production
3. Total Crude Ol to Refineries
4. Petroleum Refining
5. Gathering and Boostmg
•Data EclkKlon tog an In HY 2D16
6. Gas Processing Plant
"May conlan NGL fraclBnation «julpmorrt
7. Najural Gas Liquids INGL) Supply
8. Trarsmission Compressor Stations
9. Underground Storage
10. Liquified Naturaf Gas
-------
associations, consultants and environmental organizations in preparing the
inventory.
The Greenhouse Gas Inventory represents the EPA's official nationwide estimate
for oil and natural gas production methane emissions. The inventory provides an
estimate of emissions for the entire universe of U.S. sources for every year since
1990. The most recent inventory was published in 2017 and covers 1990-2015.
For 2015, the Greenhouse Gas Inventory estimated that oil and natural gas
production emitted 145.6 million metric tons CChe of methane. This accounted
for 22.2 percent of all methane emissions and 2.5 percent of all greenhouse gas
emissions in the inventory.
Greenhouse Gas Inventory Development Process
The EPA updates the Greenhouse Gas Inventory each year. For most oil and
natural gas production sources, the EPA develops estimates based on the number
of wells for a given year, as reported in an industry database called Drillinglnfo.
The EPA generally develops estimates for specific types of equipment
(e.g., separators, pneumatic controllers) by determining the average number of
that type of equipment located at a well. This is referred to as activity data or an
activity factor. The per-well activity factors are applied to national well counts to
calculate total national activity data. The EPA then applies an emission factor to
the national activity data to estimate emissions. The Greenhouse Gas Inventory
draws from a number of information sources for emission factors and activity
data, including a 1996 study conducted by the EPA and the Gas Research
Institute, other federal agencies, and industry research. As data from the
Greenhouse Gas Reporting Program have become available in recent years,
that data have been incorporated into the inventory as appropriate.
In accordance with the 2006 IPCC guidelines, the EPA attempts each year to
improve the analyses in the Greenhouse Gas Inventory through better data and
methods. In addition, inventory staff revise production emission estimates as new
data become available. To do so, Greenhouse Gas Inventory staff follow a process
for updating new versions of the inventory, which involves evaluating newly
available or updated data, and seeking expert and public feedback on proposed
methodological revisions.
Each year, inventory staff identify new or updated data made available
through the Greenhouse Gas Reporting Program, external studies and updates to
existing external information sources, such as Drillinglnfo, and assess whether
information or methods in the inventory should be revised. Inventory staff request
feedback from industry experts and the public on potential new data sources and
methods, through memorandums issued to a listserv of experts and posted on the
EPA's website. Before finalizing the inventory report, the EPA also seeks public
comment on the entire draft inventory by publishing it in the Federal Register.
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Figure 3 depicts the process used to incorporate new data and methodological
changes into the Greenhouse Gas Inventory.
Figure 3: Process for considering new data and revising the Greenhouse Gas Inventory
External studies
Data and
methods from
previous year's
inventory
Issue final
Greenhouse
Gas Inventory
Greenhouse
Gas Reporting
Program
*
Review newly
available and
updated data
for production
sources
Industry databases or
other external sources
Assess
comments and
make changes as
appropriate
*
~
Develop proposed
revisions based
on updated and
new data as
appropriate
Publish the full
Greenhouse Gas
Inventory draft
in the Federal
Register for
public comment
4
Issue
memorandums on
new data and
proposed revisions
for stakeholder
feedback
~
Assess feedback
and make changes
as appropriate
Source: OIG analysis based on Greenhouse Gas Inventory documentation.
EPA Considered Information Related to the EDF/UT-Austin Studies
as Part of Its Inventory Development Process
As part of its efforts to review newly available data for oil and natural gas
production sources, the EPA invited the EDF/UT-Austin study teams to present
the results of their 2013 and 2014 studies. Presentations for the two studies
occurred in September 2013 and December 2014, respectively.
Also in 2014, staff from the EPA's Office of Atmospheric Programs received a
briefing from the agency's Office of Research and Development staff, who had
experience using a Hi Flow Sampler similar to the one used in the EDF/UT-
Austin studies. Office of Research and Development staff had observed problems
with the Hi Flow Sampler in 2011, when using the device in a study to measure
leaks at condensate tanks at oil and gas production facilities.10 Emissions from
those tanks were high in hydrocarbons, and Office of Research and Development
staff theorized that the hydrocarbons overwhelmed the Hi Flow Sampler's
sensors, causing the device to malfunction.
111 This study used the Hi Flow Sampler to measure emissions from multiple sources at oil and natural gas production
facilities. The research team observed problems with the device only when measuring large emissions from
condensate tanks. In 2012, an EPA contractor presented a paper on the experiences with the Hi Flow Sampler in this
study at an Air and Waste Management Association meeting.
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Office of Research and Development staff told us that during the 2014 briefing to
the Office of Atmospheric Programs, they notified them about forthcoming
concerns from Mr. Howard about the Hi Flow Sampler.
In 2015, a journal article and formal comments by Mr. Howard were published
critiquing the measurements made with the Hi Flow Sampler in the EDF/UT-
Austin studies. He also expressed his concerns to EPA staff via email. In February
2016, Mr. Howard formally presented his concerns to EPA staff and others,
including members of the press, via a teleconference/internet presentation.
The EPA formally requested comment on the EDF/UT-Austin studies and the Hi
Flow Sampler in memorandums for the 1990-2013 and 1990-2014 Greenhouse
Gas Inventories. Specifically, in memorandums issued in 2015 and 2016,
inventory staff requested stakeholder feedback on the following:
• Specific aspects of the EDF/UT-Austin studies related to pneumatic
controllers and how data could potentially be used for the Greenhouse Gas
Inventory.
• Whether potential problems with Hi Flow Sampler measurements may
have affected new studies of emissions from transmission and distribution
segments, and whether methods exist for recalculating some of the data
points to correct for potential Hi Flow Sampler problems.
In the years since publication of the EDF/UT-Austin studies, EPA staff have also
attended events where Mr. Howard presented his concerns, and used the
occasions to engage stakeholders on potential problems with the Hi Flow
Sampler.
Extent and Significance of Device Malfunction in Production
Measurements Have Not Been Established
While there is evidence that some Hi Flow Samplers have failed under certain
conditions, the extent and significance of these failures have not been established
in studies. Researchers in the EPA's Office of Research and Development
encountered a malfunction when using the device to measure tank emissions in
the production sector in 2011, and the researcher who oversaw the measurements
for the EDF/UT-Austin production segment studies told us Mr. Howard is correct
that the Hi Flow Sampler can fail under certain circumstances. However, the
researcher does not believe these failures occur as frequently as Mr. Howard
claims.
Further, Dr. Allen, the lead researcher of the EDF/UT-Austin production segment
studies, said he has seen no evidence of the sensor failures described by Mr.
Howard, though one of his Hi Flow Samplers shut down during field testing that
was conducted after the 2013 study. We found that there has not been sufficient
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testing to determine specific conditions in which the device might malfunction,
how prevalent the problem might be (i.e., are only some devices faulty or is it a
systemic problem), or whether there are operational best practices that could
mitigate the problem.
To date, field testing has been conducted with only several devices, and results
have been inconclusive. The researcher who oversaw the measurements for the
2013 and 2014 EDF/UT-Austin studies views Mr. Howard's concerns as a
valuable part of the scientific process for assessing measurements taken with the
Hi Flow Sampler. Use of the Hi Flow Sampler to measure gas streams for which
it was not specifically designed led the manufacturer of the Hi Flow Sampler to
update its user manual to caution against the device being used to measure high
hydrocarbon gas streams.
Claim That the Device Can Malfunction in Other Segments Is
Unproven
In two journal articles, Mr. Howard concluded that the Hi Flow Sampler can also
malfunction when measuring gas streams with very high methane content and low
hydrocarbons, such as those found in the transmission and processing segments
where the device is approved for measurement of some sources under Subpart W.
Mr. Howard based his conclusions on analyses of measurements taken in other
studies, including the 2013 EDF/UT-Austin study. Mr. Howard did not conduct
any direct testing where he encountered and/or documented a failure when
measuring very high methane content gas streams.
EPA staff we spoke with are not aware of any data that indicate the Hi Flow
Sampler malfunctions in high methane content gas streams. Thus, the EPA has
not made any revisions to the approved methods for high-volume samplers
(including the Hi Flow Sampler) in the Greenhouse Gas Reporting Program for
certain sources in the transmission and processing segments. We believe this is
appropriate for the following reasons:
• Malfunction of the device in these segments is unproven.
• The EPA approved these methods for use as intended by the manufacturer.
• EPA staff are aware of the concerns and are tracking the issue.
• The Greenhouse Gas Reporting Program is not intended to assess
compliance with any particular standard, and thus some degree of
uncertainty is tolerable.
• EPA staff sought feedback on the issue through Greenhouse Gas Inventory
memorandums issued in 2015 and 2016.
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EPA Has Not Used EDF/UT-Austin Studies for Official Emission
Estimation or Rulemaking Purposes
As stated above, Greenhouse Gas Inventory staff considered and requested
comment on various aspects of the EDF/UT-Austin studies. However, the EPA
ultimately did not make any methodological revisions to the inventory based on
the EDF/UT-Austin studies, and data from the studies have not been incorporated
into the inventory. The EPA also has not made any revisions to the emission
factors or calculations for production sources in Subpart W of the Greenhouse
Gas Reporting Program based on these studies. In addition, while the EPA
consulted the studies, along with a number of other information sources during
the rulemaking process to set New Source Performance Standards to limit
methane emissions from the oil and natural gas industry, the EPA did not use any
data from the studies to set the final standards issued in 2016.
EPA Researchers Developed an Augmented Protocol for Hi Flow
Sampler Use
After experiencing Hi Flow Sampler
malfunctioning in its earlier research,
the EPA's Office of Research and
Development developed an augmented
(work-around) approach for using the
device for field measurements. In a 2015
study at production sites, staff from EPA
Region 8 and the Office of Research and
Development measured and analyzed the
hydrocarbon content of the gas stream
with a probe as an additional quality
assurance step for each measurement it
took with the Hi Flow Sampler. In
addition, the Office of Research and
Development is currently attempting to
develop a new high-volume sampler for
internal agency use.
In October 2017, Office of Research and
Development staff, in conjunction with
staff from EPA Region 8, were awarded
funding of $100,000 through the EPA
Regional Applied Research Effort
program to develop and test a new high-volume
sampler prototype.11 The main impetus for this development is that the
manufacturer is no longer producing the l fi Flow Sampler, and there are currently
11 Office of Research and Development staff told us they may receive an additional $25,000 in funding for the
project in fiscal year 2019.
Researchers using a Hi Flow Sampler, and a
hand-held probe for quality assurance, at a
production site in Utah. (EPA photo)
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no high-volume samplers commercially available, although an Office of Research
and Development researcher told us they also hope to improve on the design of
the Hi Flow Sampler to eliminate any potential malfunction problems. The
researcher told us this undertaking is complicated by safety considerations, and
they are determining whether additional funding will be needed to complete the
project.
Conclusion
EPA staff were aware of potential concerns raised about the EDF/UT-Austin
studies and used the agency's internal review processes to evaluate data and
solicit stakeholder feedback. Specifically, the EPA used its annual Greenhouse
Gas Inventory development process to consider data from the studies, and sought
stakeholder feedback on aspects of the studies through memorandums when
developing the 1990-2013 and 1990-2014 inventories. The EPA ultimately did
not make any changes to the inventory or to the Greenhouse Gas Reporting
Program based on data from the studies. In addition, the EPA did not use data
from the studies to set the 2016 New Source Performance Standards to limit
methane emissions from the oil and natural gas industry.
The EPA also used the Greenhouse Gas Inventory development process to solicit
expert feedback on the Hi Flow Sampler. High-volume samplers, such as the
Hi Flow Sampler, remain approved reporting tools under the Greenhouse Gas
Reporting Program for certain large sources in the oil and natural gas transmission
and processing segments. We did not find any conclusive evidence indicating
device malfunctions in those segments.
Agency Response and OIG Evaluation
The agency provided technical comments on the draft version of this report.
We have made changes as appropriate based on those comments.
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Distribution
The Administrator
Chief of Staff
Chief of Operations
Deputy Chief of Operations
Assistant Administrator for Air and Radiation
Agency Follow-Up Official (the CFO)
Agency Follow-Up Coordinator
General Counsel
Associate Administrator for Congressional and Intergovernmental Relations
Associate Administrator for Public Affairs
Career Deputy Assistant Administrator for Air and Radiation
Director, Office of Atmospheric Programs, Office of Air and Radiation
Audit Follow-Up Coordinator, Office of the Administrator
Audit Follow-Up Coordinator, Office of Air and Radiation
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