# Air Quality: Revision to the Regulatory Definition of Volatile Organic Compounds-Exclusion of (2E)-1,1,1,4,4,4-hexafluorobut-2-ene (HFO-1336mzz(E))
> **Rule** · Final rule. · Published 2023-02-08 · Effective 2023-04-10 · 88 FR 8226
## Document
- **Document number:** 2023-02384
- **Category:** air-emissions
- **Federal Register citation:** 88 FR 8226
- **CFR reference:** 40 CFR 51
- **Publication date:** 2023-02-08
- **Effective date:** 2023-04-10
- **EPA docket:** EPA-HQ-OAR-2021-0420
## Abstract

On April 28, 2022, the U.S. Environmental Protection Agency (EPA) published a proposed rule seeking comments in response to a petition requesting the revision of the EPA's regulatory definition of volatile organic compounds (VOC) to exempt trans-1,1,1,4,4,4- hexafluorobut-2-ene (also known as HFO-1336mzz(E); CAS number 66711-86- 2). The EPA is now taking final action to revise the regulatory definition of VOC under the Clean Air Act (CAA). This final action adds HFO-1336mzz(E) to the list of compounds excluded from the regulatory definition of VOC on the basis that this compound makes a negligible contribution to tropospheric ozone (O<INF>3</INF>) formation.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2023/02/08/2023-02384/air-quality-revision-to-the-regulatory-definition-of-volatile-organic-compounds-exclusion-of)
---
*AI Analytics · CC0 1.0*