42 USC § 7478 - Period before plan approval

---
identifier: "/us/usc/t42/s7478"
source: "usc"
legal_status: "official_prima_facie"
title: "42 USC § 7478 - Period before plan approval"
title_number: 42
title_name: "THE PUBLIC HEALTH AND WELFARE"
section_number: "7478"
section_name: "Period before plan approval"
chapter_number: 85
chapter_name: "AIR POLLUTION PREVENTION AND CONTROL"
subchapter_number: "I"
subchapter_name: "PROGRAMS AND ACTIVITIES"
part_number: "C"
part_name: "Prevention of Significant Deterioration of Air Quality"
positive_law: false
currency: "119-84"
last_updated: "2026-04-17"
format_version: "1.1.0"
generator: "[email protected]"
source_credit: "(July 14, 1955, ch. 360, title I, § 168, as added Pub. L. 95–95, title I, § 127(a), Aug. 7, 1977, 91 Stat. 740; amended Pub. L. 95–190, § 14(a)(52), Nov. 16, 1977, 91 Stat. 1402.)"
---


# § 7478. Period before plan approval

**(a)** **Existing regulations to remain in effect** August 7, 1977

Until such time as an applicable implementation plan is in effect for any area, which plan meets the requirements of this part to prevent significant deterioration of air quality with respect to any air pollutant, applicable regulations under this chapter prior to , shall remain in effect to prevent significant deterioration of air quality in any such area for any such pollutant except as otherwise provided in subsection (b).

**(b)** **Regulations deemed amended; construction commenced after June 1, 1975** August 7, 1977section 7474(a) of this titlesection 7479(2) of this titleJune 1, 1975August 7, 1977August 7, 1977

If any regulation in effect prior to , to prevent significant deterioration of air quality would be inconsistent with the requirements of section 7472(a), section 7473(b) or , then such regulations shall be deemed amended so as to conform with such requirements. In the case of a facility on which construction was commenced (in accordance with the definition of “commenced” in ) after , and prior to , the review and permitting of such facility shall be in accordance with the regulations for the prevention of significant deterioration in effect prior to .

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**Source Credit**: (July 14, 1955, ch. 360, title I, § 168, as added Pub. L. 95–95, title I, § 127(a), Aug. 7, 1977, 91 Stat. 740; amended Pub. L. 95–190, § 14(a)(52), Nov. 16, 1977, 91 Stat. 1402.)

## Editorial Notes

### Amendments

1977—Subsec. (b).  substituted “(in accordance with the definition of ‘commenced’ in )” for “in accordance with this definition”.