# Approval and Promulgation of Air Quality Implementation Plans; State of Montana; Billings Carbon Monoxide Redesignation to Attainment and Designation of Areas for Air Quality Planning Purposes
> **Rule** · Direct final rule. · Published 2002-02-21 · Effective 2002-04-22 · 67 FR 7966
## Document
- **Document number:** 02-4062
- **Category:** air-emissions
- **Federal Register citation:** 67 FR 7966
- **CFR reference:** 40 CFR 52
- **Publication date:** 2002-02-21
- **Effective date:** 2002-04-22
- **State:** MT
- **EPA docket:** MT-001-0036a
## Abstract

On February 9, 2001, the Governor of Montana submitted a request to redesignate the Billings "not classified" carbon monoxide (CO) nonattainment area to attainment for the CO National Ambient Air Quality Standard (NAAQS). The Governor also submitted a CO maintenance plan. In this action, EPA is approving the Billings CO redesignation request and the maintenance plan.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2002/02/21/02-4062/approval-and-promulgation-of-air-quality-implementation-plans-state-of-montana-billings-carbon)
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