eCFR Reference Browser

---

title: "40 CFR §51.151"

source: "https://www.ecfr.gov/current/title-40/section-51.151"

title_number: "40"

volume_number: "2"

chapter_number: "Unknown"

subchapter_code: "C"

subchapter_subject: "AIR PROGRAMS"

part_code: "51"

part_subject: "REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS"

subpart_code: "H"

subpart_subject: "Prevention of Air Pollution Emergency Episodes"

section_number: "51.151"

section_subject: "Significant harm levels."

cfr_reference: "40 CFR 51.151"

title_name: "Title 40"

title_subject: "Protection of Environment"

parts_covered: "Parts 50 to 51"

revised_date: "Revised as of July 1, 2019"

publication_date: "As of July 1, 2019"

contains_description: "Containing a codification of documents of general applicability and future effect"

publication_info: "Published by the Office of the Federal Register National Archives and Records Administration as a Special Edition of the Federal Register"

---

Each plan for a Priority I region must include a contingency plan which must, as a minimum, provide for taking action necessary to prevent ambient pollutant concentrations at any location in such region from reaching the following levels:

§51.151 - Significant harm levels.