# Final Rule To Implement the 1997 8-Hour Ozone National Ambient Air Quality Standard: Classification of Areas That Were Initially Classified Under Subpart 1; Revision of the Anti-Backsliding Provisions To Address 1-Hour Contingency Measure Requirements; Deletion of Obsolete 1-Hour Ozone Standard Provision
> **Rule** · — · Published 2012-07-25 · 77 FR 43521
## Document
- **Document number:** C1-2012-11232
- **Category:** air-emissions
- **Federal Register citation:** 77 FR 43521
- **CFR reference:** 40 CFR 81
- **Publication date:** 2012-07-25
- **EPA docket:** EPA-HQ-OAR-2007-0956
## Source
- [Federal Register document](https://www.federalregister.gov/documents/2012/07/25/C1-2012-11232/final-rule-to-implement-the-1997-8-hour-ozone-national-ambient-air-quality-standard-classification)
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