---
kind: "unit"
title: "40"
title_heading: "Protection of Environment"
key: "chI/subchC/part52/subpartLL"
level: "subpart"
label: "Subpart LL"
heading: "Oklahoma"
release: "ecfr-current"
date: "2026-08-27"
url: "https://uscodex.org/cfr/40/chI-subchC-part52-subpartLL"
sections_count: 14
---

# Subpart LL — Oklahoma

Title 40 C.F.R. — Protection of Environment › Chapter I — Environmental Protection Agency › Subchapter C — Air Programs › Part 52 — Approval and Promulgation of Implementation Plans

## Sections

- [§52.1919. Reserved](/cfr/40/52.1919.md)
- [§52.1920. Identification of plan.](/cfr/40/52.1920.md)
- [§52.1921. Classification of regions.](/cfr/40/52.1921.md)
- [§52.1922. Approval status.](/cfr/40/52.1922.md)
- [§52.1923. Best Available Retrofit Requirements (BART) for SO 2 and Interstate pollutant transport provisions; What are the FIP requirements for Units 4 and 5 of the Oklahoma Gas and Electric Muskogee plant; and Units 1 and 2 of the Oklahoma Gas and Electric Sooner plant affecting visibility?](/cfr/40/52.1923.md)
- [§52.1924-52.1927. Reserved](/cfr/40/52.1924-52.1927.md)
- [§52.1928. Visibility protection.](/cfr/40/52.1928.md)
- [§52.1929. Significant deterioration of air quality.](/cfr/40/52.1929.md)
- [§52.1930. Interstate pollutant transport provisions; What are the FIP requirements for decreases in emissions of nitrogen oxides?](/cfr/40/52.1930.md)
- [§52.1931. Petroleum storage tank controls.](/cfr/40/52.1931.md)
- [§52.1932-52.1933. Reserved](/cfr/40/52.1932-52.1933.md)
- [§52.1934. Prevention of air pollution emergency episodes.](/cfr/40/52.1934.md)
- [§52.1935. Small business assistance program.](/cfr/40/52.1935.md)
- [§52.1960. Original Identification of plan section.](/cfr/40/52.1960.md)