---
kind: "unit"
title: "40"
title_heading: "Protection of Environment"
key: "chI/subchC/part51/subpartW"
level: "subpart"
label: "Subpart W"
heading: "Determining Conformity of General Federal Actions to State or Federal Implementation Plans"
release: "ecfr-current"
date: "2026-08-27"
url: "https://uscodex.org/cfr/40/chI-subchC-part51-subpartW"
sections_count: 3
---

# Subpart W — Determining Conformity of General Federal Actions to State or Federal Implementation Plans

Title 40 C.F.R. — Protection of Environment › Chapter I — Environmental Protection Agency › Subchapter C — Air Programs › Part 51 — Requirements for Preparation, Adoption, and Submittal of Implementation Plans

## Sections

- [§51.850. Reserved](/cfr/40/51.850.md)
- [§51.851. State implementation plan (SIP) or Tribal implementation plan (TIP) revision.](/cfr/40/51.851.md)
- [§51.852-51.860. Reserved](/cfr/40/51.852-51.860.md)