EPA's Supplemental Proposal to Reduce Pollution from Oil and Natural Gas Operations to
Fight the Climate Crisis and Protect Public Health:

Using Optical Gas Imaging in Leak Detection (Appendix K)

Fact Sheet

Summary

•	The U.S. Environmental Protection Agency (EPA) is proposing to update, strengthen and
expand its November 2021 proposal that would secure major climate and health benefits
for all Americans by reducing emissions of methane and other harmful air pollution from
both new and existing sources in the oil and natural gas industry.

•	In a supplemental proposal signed November 8, 2022, EPA would achieve more
comprehensive emissions reductions from oil and natural gas facilities by improving
standards in the 2021 proposal and adding proposed requirements for sources not
previously covered by the rules.

•	The supplemental proposal also includes updates to the proposed protocol for using optical
gas imaging (OGI), also known as "Appendix K." OGI identifies methane leaks and other
emissions using a thermal infrared camera.

•	The proposed Appendix K would apply only if a rule specifies that Appendix K should be
used. Under the supplemental proposal for the oil and natural gas industry, it would apply
to OGI surveys used to detect leaks at onshore natural gas processing plants.

•	The proposed Appendix K includes requirements for the performance of infrared cameras,
operator training, developing operating envelopes for surveys, monitoring plans, and
recordkeeping. Operating envelope refers to the range of conditions within which a survey
must be conducted to achieve the quality objective.

•	To develop the proposed Appendix K requirements, EPA conducted a literature review of
technology development and examined current applications of OGI technology. EPA
commissioned laboratory studies and OGI technology evaluations and hosted a virtual
workshop to gather input on OGI use and rule development.

•	EPA will take public comment for 60 days after the rule is published in the Federal Register.
The Agency also will hold a virtual public hearing.

Proposed Requirements

•	After reviewing public comments on the November proposal, EPA is proposing several
changes to Appendix K:

1


-------
Operator Standards

Training

•	The supplemental proposal would require OGI operators to complete initial
classroom training followed by refresher training every two years. That training can
be online or in person. Initial field training with a senior OGI camera operator would
last at least 30 hours, followed by a final field test lasting at least two hours. The
field training requirements would allow for 10 percent missed leaks if there are
more than 10 leaks total during the final field test. Trainees who fail the final field
test may repeat the test after the senior OGI camera operator provides instruction
on performance improvement

Senior Operator Requirements

•	The supplemental proposal would define "senior OGI camera operator" as
operators who have logged 1,400 survey hours during their career, including 40
hours in the past 12 months, and who have developed or completed the classroom
training. Senior OGI operators who performed monitoring as part of initial field
training, retraining, or while auditing other operators could include those
monitoring hours in determining senior OGI camera operator classification.

Audits

•	All OGI operators would be required to complete a two-hour audit four times a
year. Operators who do not pass the audit would need to retrain for at least 16
hours with a senior OGI camera operator, followed by a final field test. Operators
would need to complete initial training again if the operator fails two consecutive
audits.

Inactive Operators

•	OGI camera operators who have been inactive would be eligible to retrain instead
of completing the initial training.

Previous Experience

•	EPA is proposing to grandfather current OGI camera operators to reduce the
amount of initial training required.

•	Operators with previous classroom training would not be required to take the initial
classroom training. However, operators may have to take biennial classroom
training if they took the previous classroom training more than two years before
Appendix K is finalized.

2


-------
•	Operators with previous field experience may be eligible to complete the retraining
requirements in lieu of completing the initial field training requirements. Retraining
consists of eight survey hours with a senior OGI camera operator conducting side-
by-side surveys, eight hours of independent survey performance observed by a
senior OGI camera operator, and a final monitoring survey test.

Requirements for using OGI - technical details

Dwell Time

•	Dwell time is the time required to survey a scene to provide adequate probability of
leak detection. Dwell time is the active time the operator is looking for potential
leaks and does not begin until the scene is in focus and steady.

•	EPA is proposing to reduce the dwell time (the active time an operator is looking for
potential leaks when the scene is in focus and steady) to two seconds per
component in the field of view.

Documentation

•	OGI camera operators would have the flexibility to use either video clips or a photo
to document a leak. OGI camera operators could also use full videos in place of
clips.

•	The proposal clarifies which records must be kept on-site and the length of time
that records must be kept.

Camera requirements

•	EPA is proposing to require that an OGI camera must be capable of methane
emissions of 17 grams per hour and either butane emissions of 5.0 grams per hour
or propane emissions of 18 grams per hour at a viewing distance of 2 meters and a
delta-T of 5 degrees Celsius in an environment of calm wind conditions.

•	EPA is clarifying that initial camera certifications and "operating envelope"
determinations could be conducted by the owner or operator, the camera
manufacturer, or a third party. An operating envelope is the range of conditions in
which a survey must be conducted. Rest Breaks

•	The supplemental proposal would require rest breaks every 30 minutes for all OGI
operators to reduce physical, mental, and eye fatigue.

Response Factors

•	Response factors are used as a reference to propane to determine the camera's
ability to detect fugitive emissions. The supplemental proposal includes a

3


-------
procedure for developing camera model response factors. EPA is adding this
procedure as an annex to the Appendix.

For More Information

• Read the supplemental proposal and additional fact sheets.

4


-------