# Air Quality Plan; Arizona; Maricopa County Air Quality Department; New Source Review; Emission Reduction Credits-Rule 204

**Action Urgency Score:** 55/100

| Field | Value |
|---|---|
| Agency | Environmental Protection Agency |
| Type | Proposed rule |
| Action | Proposed rule. |
| Published | 2026-10-08 |
| Comments close | 2026-11-09 |
| Significant | No |
| CFR parts | 40 CFR 52 |
| Summary | 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 stationar |
| Document number | 2026-20612 |

## Why this score
- Comment deadline within 30 days.

Source: Federal Register API (Office of the Federal Register) (https://www.federalregister.gov/documents/2026/10/08/2026-20612/air-quality-plan-arizona-maricopa-county-air-quality-department-new-source-review-emission-reduction). Last refreshed: 2026-11-03T19:10:06.902Z.
Data from the Federal Register API; the published Federal Register document is authoritative. Informational only, not legal advice.