# Approval and Promulgation of Air Quality Implementation Plans; Colorado; Regional Haze State Implementation Plan
> **Rule** · Final rule. · Published 2018-07-05 · Effective 2018-08-06 · 83 FR 31332
## Document
- **Document number:** 2018-14387
- **Category:** air-emissions
- **Federal Register citation:** 83 FR 31332
- **CFR reference:** 40 CFR 52
- **Publication date:** 2018-07-05
- **Effective date:** 2018-08-06
- **State:** CO
- **EPA docket:** EPA-R08-OAR-2018-0015
## Abstract

The Environmental Protection Agency (EPA) is approving State Implementation Plan (SIP) revisions submitted by the State of Colorado on May 26, 2017, addressing regional haze. The revisions include source-specific revisions to the nitrogen oxides (NO<INF>X</INF>) best available retrofit technology (BART) determination for Craig Station Unit 1 and to the NO<INF>X</INF> reasonable progress determination for the Nucla Station. Both Craig Station Unit 1 and Nucla Station are owned in part and operated by Tri-State Generation & Transmission Association, Inc. (Tri-State). The EPA is taking this action pursuant to section 110 of the Clean Air Act (CAA).

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2018/07/05/2018-14387/approval-and-promulgation-of-air-quality-implementation-plans-colorado-regional-haze-state)
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