40 CFR § 61.191 - Definitions.
---
identifier: "/us/cfr/t40/s61.191"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 61.191 - Definitions."
title_number: 40
title_name: "Protection of Environment"
section_number: "61.191"
section_name: "Definitions."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "C"
subchapter_name: "AIR PROGRAMS"
part_number: "61"
part_name: "NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS"
positive_law: false
currency: "2026-04-05"
last_updated: "2026-04-05"
format_version: "1.1.0"
generator: "[email protected]"
authority: "42 U.S.C. 7401"
regulatory_source: "38 FR 8826, Apr. 6, 1973, unless otherwise noted."
cfr_part: "61"
---
# 61.191 Definitions.
As used in this subpart, all terms not defined here have the meaning given them in the Clean Air Act or subpart A of part 61. The following terms shall have the following specific meanings:
(a) *Facility* means all buildings, structures and operations on one contiguous site.
(b) *Source* means any building, structure, pile, impoundment or area used for interim storage or disposal that is or contains waste material containing radium in sufficient concentration to emit radon-222 in excess of this standard prior to remedial action.