---
kind: "section"
citation: "40 C.F.R. § 52.1382"
title: "40"
number: "52.1382"
heading: "Prevention of significant deterioration of air quality."
url: "https://uscodex.org/cfr/40/52.1382"
---

# §52.1382. Prevention of significant deterioration of air quality.

- (a) The Montana plan, as submitted, is approved as meeting the requirements of Part C, [Subpart 1](/cfr/40/subpart1.md) of the Clean Air Act, except that it does not apply to sources proposing to construct on Indian Reservations.
- (b) **Regulation for preventing significant deterioration of air quality.** The provisions of [§ 52.21](/cfr/40/52.21.md) except paragraph (a)(1) are hereby incorporated and made a part of the Montana State implementation plan and are applicable to proposed major stationary sources or major modifications to be located on Indian Reservations.
- (c)
  - (1) **Except as set forth in this paragraph, all areas of Montana are designated Class II.**
  - (2) **The Northern Cheyene Indian Reservation is designated Class I.**
  - (3) **The Flathead Indian Reservation is designated Class I.**
  - (4) **The Fort Peck Indian Reservation is designated Class I.**

## Notes

### Amendments

[42 FR 40697, Aug. 11, 1977, as amended at 47 FR 23928, June 2, 1982; 48 FR 20233, May 5, 1983; 49 FR 4735, Feb. 8, 1984; 53 FR 48645, Dec. 2, 1988; 55 FR 19262, May 9, 1990; 55 FR 22333, June 1, 1990; 68 FR 11323, Mar. 10, 2003; 68 FR 74489, Dec. 24, 2003]

### Authority

Authority: 42 U.S.C. 7401 et seq.

### Amendments

[40 FR 5521, Feb. 6, 1975]

### Amendments

[42 FR 40697, Aug. 11, 1977, as amended at 47 FR 23928, June 2, 1982; 48 FR 20233, May 5, 1983; 49 FR 4735, Feb. 8, 1984; 53 FR 48645, Dec. 2, 1988; 55 FR 19262, May 9, 1990; 55 FR 22333, June 1, 1990; 68 FR 11323, Mar. 10, 2003; 68 FR 74489, Dec. 24, 2003]