# Approval and Promulgation of Air Quality Implementation Plans; Indiana; Carbon Monoxide Maintenance Plan Updates; Limited Maintenance Plan
> **Rule** · Direct final rule. · Published 2009-10-15 · Effective 2009-12-14 · 74 FR 52891
## Document
- **Document number:** E9-24695
- **Category:** air-emissions
- **Federal Register citation:** 74 FR 52891
- **CFR reference:** 40 CFR 52
- **Publication date:** 2009-10-15
- **Effective date:** 2009-12-14
- **State:** IN
- **EPA docket:** EPA-R05-OAR-2009-0120
## Abstract

The Indiana Department of Environmental Management (IDEM) submitted Carbon Monoxide (CO) "Limited Maintenance Plan" updates for Lake and Marion Counties on January 12, 2009. These Limited Maintenance Plans demonstrate continued attainment of the CO National Ambient Air Quality Standard (NAAQS) for Lake and Marion counties for an additional ten years. EPA is, therefore, approving it into Indiana's State Implementation Plan (SIP).

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2009/10/15/E9-24695/approval-and-promulgation-of-air-quality-implementation-plans-indiana-carbon-monoxide-maintenance)
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