{"abstract":"The U.S. Environmental Protection Agency (EPA) is proposing to approve a revision to the Maricopa County Air Quality Department (MCAQD or \"Department\") portion of the Arizona State Implementation Plan (SIP). This revision establishes a federally enforceable program allowing nonroad engine fleet owners/operators to generate emission reduction credits (ERCs) by either retrofitting their nonroad engines or replacing their nonroad engines with lower-emitting nonroad engines while meeting other Clean Air Act (CAA or \"Act\") requirements. These ERCs are intended for use as offsets for major stationary sources under the Department's Nonattainment New Source Review (NNSR) program. We are proposing to approve a local rule to allow for the generation of ERCs through voluntary nonroad engine emission reductions under the CAA.","action":"Proposed rule.","agencies":[{"raw_name":"ENVIRONMENTAL PROTECTION AGENCY","name":"Environmental Protection Agency","id":145,"url":"https://www.federalregister.gov/agencies/environmental-protection-agency","json_url":"https://www.federalregister.gov/api/v1/agencies/145","parent_id":null,"slug":"environmental-protection-agency"}],"body_html_url":"https://www.federalregister.gov/documents/full_text/html/2026/10/08/2026-20612.html","cfr_references":[{"chapter":null,"citation_url":null,"part":"52","title":40}],"citation":"91 FR 64321","comment_url":"http://www.regulations.gov/commenton/EPA-R09-OAR-2026-4654-0001","comments_close_on":"2026-11-09","correction_of":null,"corrections":[],"dates":"Comments must be received on or before November 9, 2026.","disposition_notes":null,"docket_ids":["EPA-R09-OAR-2026-4654","FRL-13434-01-R9"],"dockets":[{"supporting_documents":[{"title":"C. EPA Guidance Documents, Policies, and Rulemakings","document_id":"EPA-R09-OAR-2026-4654-0005"},{"title":"B. Supporting Materials and Other Documents","document_id":"EPA-R09-OAR-2026-4654-0004"},{"title":"A. State Implementation Plan Submittal Documents","document_id":"EPA-R09-OAR-2026-4654-0003"},{"title":"Docket Index NPRM EPA-R09-OAR-2026-4654","document_id":"EPA-R09-OAR-2026-4654-0002"}],"agency_name":"EPA","documents":[{"comment_count":3,"comment_start_date":"2026-10-08","updated_at":"2026-10-09T01:56:41.668-04:00","comment_url":"https://www.regulations.gov/commenton/EPA-R09-OAR-2026-4654-0001","allow_late_comments":false,"id":"EPA-R09-OAR-2026-4654-0001","comment_end_date":"2026-11-10","regulations_dot_gov_open_for_comment":true}],"supporting_documents_count":4,"id":"EPA-R09-OAR-2026-4654","title":"Air Quality Plan; Arizona; Maricopa County Air Quality Department; New Source Review; Emission Reduction Credits - Rule 204"}],"document_number":"2026-20612","effective_on":null,"end_page":64324,"executive_order_notes":null,"executive_order_number":null,"full_text_xml_url":"https://www.federalregister.gov/documents/full_text/xml/2026/10/08/2026-20612.xml","html_url":"https://www.federalregister.gov/documents/2026/10/08/2026-20612/air-quality-plan-arizona-maricopa-county-air-quality-department-new-source-review-emission-reduction","images":{},"images_metadata":{},"json_url":"https://www.federalregister.gov/api/v1/documents/2026-20612?publication_date=2026-10-08","mods_url":"https://www.govinfo.gov/metadata/granule/FR-2026-10-08/2026-20612/mods.xml","not_received_for_publication":null,"page_length":4,"page_views":{"count":132,"last_updated":"2026-10-09 14:15:06 -0400"},"pdf_url":"https://www.govinfo.gov/content/pkg/FR-2026-10-08/pdf/2026-20612.pdf","presidential_document_number":null,"proclamation_number":null,"public_inspection_pdf_url":"https://public-inspection.federalregister.gov/2026-20612.pdf?1791377114","publication_date":"2026-10-08","raw_text_url":"https://www.federalregister.gov/documents/full_text/text/2026/10/08/2026-20612.txt","regulation_id_number_info":{},"regulation_id_numbers":[],"regulations_dot_gov_info":{"supporting_documents":[{"title":"C. EPA Guidance Documents, Policies, and Rulemakings","document_id":"EPA-R09-OAR-2026-4654-0005"},{"title":"B. Supporting Materials and Other Documents","document_id":"EPA-R09-OAR-2026-4654-0004"},{"title":"A. State Implementation Plan Submittal Documents","document_id":"EPA-R09-OAR-2026-4654-0003"},{"title":"Docket Index NPRM EPA-R09-OAR-2026-4654","document_id":"EPA-R09-OAR-2026-4654-0002"}],"comments_count":3,"agency_id":"EPA","comments_url":"https://www.regulations.gov/docketBrowser?rpp=50&so=DESC&sb=postedDate&po=0&dct=PS&D=EPA-R09-OAR-2026-4654","supporting_documents_count":4,"docket_id":"EPA-R09-OAR-2026-4654","document_id":"EPA-R09-OAR-2026-4654-0001","regulation_id_number":null,"title":"Air Quality Plan; Arizona; Maricopa County Air Quality Department; New Source Review; Emission Reduction Credits - Rule 204","checked_regulationsdotgov_at":"2026-10-09T17:55:05Z"},"regulations_dot_gov_url":"http://www.regulations.gov/commenton/EPA-R09-OAR-2026-4654-0001","significant":null,"signing_date":null,"start_page":64321,"subtype":null,"title":"Air Quality Plan; Arizona; Maricopa County Air Quality Department; New Source Review; Emission Reduction Credits-Rule 204","toc_doc":"Arizona; Maricopa County Air Quality Department; New Source Review; Emission Reduction Credits Rule 204","toc_subject":"Air Quality State Implementation Plans; Approvals and Promulgations","topics":["Air pollution control","Environmental protection","Incorporation by reference","Intergovernmental relations","Nitrogen oxides","Ozone","Reporting and recordkeeping requirements","Volatile organic compounds"],"type":"Proposed Rule","volume":91}