You are using an unsupported browser. This web site is designed for the current versions of Microsoft Edge, Google Chrome, Mozilla Firefox, or Safari.
The Office of the Federal Register publishes documents on behalf of Federal agencies but does not have any authority over their programs. We recommend you directly contact the agency associated with the content in question.
If you have comments or suggestions on how to improve the www.ecfr.gov website or have questions about using www.ecfr.gov, please choose the 'Website Feedback' button below.
If you would like to comment on the current content, please use the 'Content Feedback' button below for instructions on contacting the issuing agency
Enhanced content is provided to the user to provide additional context.
This content is from the eCFR and is authoritative but unofficial.
Navigate by entering citations or phrases (eg: 1 CFR 1.1 49 CFR 172.101 Organization and Purpose 1/1.1 Regulation Y FAR).
Choosing an item from citations and headings will bring you directly to the content. Choosing an item from full text search results will bring you to those results. Pressing enter in the search box will also bring you to search results.
Background and more details are available in the Search & Navigation guide.
The in-page Table of Contents is available only when multiple sections are being viewed.
Use the navigation links in the gray bar above to view the table of contents that this content belongs to.
42 U.S.C. 7401 et seq.
This content is from the eCFR and may include recent changes applied to the CFR. The official, published CFR, is updated annually and available below under "Published Edition". You can learn more about the process here.
Subscribe to: 40 CFR 52.1279
View the most recent official publication:
These links go to the official, published CFR, which is updated annually. As a result, it may not include the most recent changes applied to the CFR. Learn more.
Information and documentation can be found in our developer resources.
The Code of Federal Regulations (CFR) is the official legal print publication containing the codification of the general and permanent rules published in the Federal Register by the departments and agencies of the Federal Government. The Electronic Code of Federal Regulations (eCFR) is a continuously updated online version of the CFR. It is not an official legal edition of the CFR.
Learn more about the eCFR, its status, and the editorial process.
Nomenclature changes to part 52 appear at 81 FR 74586, Oct. 26, 2016.
(a) [Reserved]
(b) Disapproval. EPA has disapproved the portions of Mississippi's May 29, 2012, 2008 8-hour Ozone infrastructure SIP submission; July 26, 2012, 2008 8-hour Ozone infrastructure SIP resubmission; February 28, 2013, 2010, 1-hour NO2 infrastructure SIP submission; June 20, 2013, 2010 1-hour SO2 infrastructure SIP submission; and December 8, 2015, 2012, Annual PM2.5 infrastructure SIP submission that address the visibility protection (prong 4) requirements of Clean Air Act section 110(a)(2)(D)(i)(II). EPA disapproved the prong 4 portions of these SIP submissions because Mississippi does not have a fully approved regional haze SIP that meets the requirements of 40 CFR 51.308 and because these SIP submissions do not otherwise demonstrate that emissions within the State do not interfere with other states' plans to protect visibility.
[77 FR 33657, June 7, 2012, as amended at 81 FR 33140, May 25, 2016; 86 FR 55509, Oct. 6, 2021]