40 CFR § 97.281 - General.

---
identifier: "/us/cfr/t40/s97.281"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 97.281 - General."
title_number: 40
title_name: "Protection of Environment"
section_number: "97.281"
section_name: "General."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "C"
subchapter_name: "AIR PROGRAMS"
part_number: "97"
part_name: "FEDERAL NOX BUDGET TRADING PROGRAM, CAIR NOX AND SO2 TRADING PROGRAMS, CSAPR NOX AND SO2 TRADING PROGRAMS, AND TEXAS SO2 TRADING PROGRAM"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401, 7403, 7410, 7426, 7491, 7601, and 7651,"
regulatory_source: "65 FR 2727, Jan. 18, 2000, unless otherwise noted. 71 FR 25396, 25422, and 25443, Apr. 28, 2006"
cfr_part: "97"
---


# 97.281 General.

(a) Except as otherwise provided in §§ 97.201 through 97.204, §§ 97.206 through 97.208, and subparts BBB and CCC and subparts FFF through HHH of this part, a CAIR SO<sub>2</sub> opt-in unit shall be treated as a CAIR SO<sub>2</sub> unit for purposes of applying such sections and subparts of this part.

(b) Solely for purposes of applying, as provided in this subpart, the requirements of subpart HHH of this part to a unit for which a CAIR opt-in permit application is submitted and not withdrawn and a CAIR opt-in permit is not yet issued or denied under this subpart, such unit shall be treated as a CAIR SO<sub>2</sub> unit before issuance of a CAIR opt-in permit for such unit.