---
kind: "section"
citation: "40 C.F.R. § 52.1398"
title: "40"
number: "52.1398"
heading: "Control strategy: Sulfur dioxide."
url: "https://uscodex.org/cfr/40/52.1398"
---

# §52.1398. Control strategy: Sulfur dioxide.

- (a) **Redesignation to attainment.** The EPA has determined that the Billings 2010 sulfur dioxide (SO2) nonattainment area has met the criteria under CAA [section 107(d)(3)(E)](/cfr/40/107.md?p=d-3-E) for redesignation from nonattainment to attainment for the 2010 1-hour SO2 NAAQS. The EPA is therefore redesignating the Billings 2010 SO2 nonattainment area to attainment.
- (b) The EPA is approving the maintenance plan for the Billings nonattainment area for the 2010 SO2 NAAQS submitted by the State of Montana on December 14, 2015.
- (c) **Redesignation to attainment.** The EPA has determined that the East Helena sulfur dioxide (SO2) nonattainment area has met the criteria under CAA [section 107(d)(3)(E)](/cfr/40/107.md?p=d-3-E) for redesignation from nonattainment to attainment for the 1971 primary and secondary SO2 NAAQS. The EPA is therefore redesignating the East Helena 1971 SO2 nonattainment area to attainment.
- (d) **Maintenance plan.** The EPA is approving the maintenance plan for the East Helena nonattainment area for the 1971 SO2 NAAQS submitted by the State of Montana on October 26, 2018.

## Notes

### Amendments

[81 FR 28720, May 10, 2016, as amended at 84 FR 47899, Sept. 11, 2019]

### Authority

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

### Amendments

[40 FR 5521, Feb. 6, 1975]

### Amendments

[81 FR 28720, May 10, 2016, as amended at 84 FR 47899, Sept. 11, 2019]