# Revisions to the Federal Implementation Plan for the Billings/Laurel, Montana, Sulfur Dioxide Area
> **Rule** · Final rule. · Published 2025-01-17 · Effective 2025-02-18 · 90 FR 5695
## Document
- **Document number:** 2025-00220
- **Category:** air-emissions
- **Federal Register citation:** 90 FR 5695
- **CFR reference:** 40 CFR 52
- **Publication date:** 2025-01-17
- **Effective date:** 2025-02-18
- **State:** MT
- **EPA docket:** EPA-R08-OAR-2023-0587
## Abstract

The Environmental Protection Agency (EPA) is revising a Federal Implementation Plan (FIP) applicable to sulfur dioxide (SO<INF>2</INF>) emissions from four sources located in Billings and Laurel, Montana. Specifically, the EPA is revising a portion of the FIP promulgated by the EPA in 2008 (2008 Billings/Laurel SO<INF>2</INF> FIP) by removing a provision which contained an affirmative defense for exceedances of flare emission limits during malfunctions, startups, and shutdowns. The EPA is taking this action pursuant to the Clean Air Act (CAA).

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2025/01/17/2025-00220/revisions-to-the-federal-implementation-plan-for-the-billingslaurel-montana-sulfur-dioxide-area)
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