Fact Sheet — Proposed Revisions to Appendix P to 40 CFR Part 51, Concerning
Minimum Emission Reporting Requirements in SIPs

ACTIONS

•	On February 7, 2020, the U.S. Environmental Protection Agency (EPA) proposed
revisions to its regulations guiding the preparation of state implementation plans (SIPs).
These regulations are found in 40 CFR Part 51.

•	The proposed action would revise the minimum reporting frequency requirement for
source categories listed in Appendix P to 40 CFR Part 51 from quarterly to semiannual.
This revision would be generally consistent with the current reporting frequency
requirements to which these sources are subject under other Clean Air Act programs
(e.g., New Source Performance Standards). As a result, each state could — but would not
be required to — revise its SIP to allow semiannual reporting for the four Appendix P
source categories:

o fossil fuel-fired steam generators of more than 250 million BTU per hour heat
input;

o fluid bed catalytic cracking unit catalyst regenerators at petroleum refineries;
o sulfuric acid plants; and
o nitric acid plants.

•	This action would also correct an erroneous cross-reference in Appendix P. EPA will
accept public comment on this proposal for 30 days after publication in the Federal
Register.

BACKGROUND

•	Each state is required under section 110 of the Clean Air Act to have a plan to achieve
and maintain clean air called a state implementation plan, or SIP. In general SIPs must
demonstrate how national air quality standards will be achieved, maintained, and
enforced. EPA established SIP preparation regulations in 1971, under 40 CFR Part 51.

•	In 1975, EPA added continuous emission monitoring specifications for SIPs under
Part 51 as Appendix P. At the same time, EPA added continuous emission monitoring
specifications for New Source Performance Standards (NSPS) under Part 60. Sources
subject to requirements specified under either set of regulations were required to submit
continuous emission monitor reports of their excess emissions and other information on a
quarterly basis. It was by design that the minimum requirements under the SIP
regulations for continuous emission monitoring (which states would apply to existing
sources) were similar to the requirements simultaneously added under the NSPS
regulations (which EPA would apply to new and modified sources).

•	In 1999, EPA promulgated a Burden Reduction Rule which revised numerous NSPS and
other regulations to allow sources to submit continuous emission monitoring reports
semiannually. Because the 1999 rule did not revise Appendix P to 40 CFR Part 51, the
minimum reporting frequency requirement specified in Appendix P generally no longer

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aligned with the reporting requirements under the NSPS regulations applicable to the four
Appendix P source categories.

HOW TO COMMENT

•	EPA will accept comments for 30 days after the proposal is published in the Federal
Register.

•	Comments, identified by Docket ID No. EPA-HQ-OAR-2018-0633, may be submitted by
one of the following methods:

o Go to https://www.regulations.gov and follow the online instructions for
submitting comments.

o Send comments by email to a-and-r-docket@epa. gov. Attention Docket ID
No. EPA-HQ-OAR-2018-0633.

o Fax your comments to: (202) 566-9744, Attention Docket ID. No. EPA-HQ-
OAR-2018-063 3.

o Mail your comments to: EPA Docket Center, Environmental Protection Agency,
Mail Code: 28221T, 1200 Pennsylvania Ave., NW, Washington, DC 20460,
Attention Docket ID. No. EPA-HQ-OAR-2018-0633.

o Deliver comments in person to: EPA Docket Center, 1301 Constitution Ave.,
NW, Room 3334, Washington, DC. Attention Docket ID. No. EPA-HQ-OAR-
2018-0633. Note: In-person deliveries (including courier deliveries) are only
accepted during the Docket's normal hours of operation. Special arrangements
should be made for deliveries of boxed information.

FOR MORE INFORMATION

•	For more information on developing an air quality SIP, go to EPA's website at
https://www.epa.gOv/air-qualitv-implementation-plans/develop-air-qualitv-sip#guidance.

•	For questions about this action, contact Ms. Lisa Sutton of EPA's Office of Air Quality
Planning and Standards at (919) 541-3450 or by email at sutton.lisa@epa.gov.

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