40 CFR § 63.5285 - Am I subject to this subpart?

---
identifier: "/us/cfr/t40/s63.5285"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 63.5285 - Am I subject to this subpart?"
title_number: 40
title_name: "Protection of Environment"
section_number: "63.5285"
section_name: "Am I subject to this subpart?"
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "C"
subchapter_name: "AIR PROGRAMS"
part_number: "63"
part_name: "NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES"
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"
regulatory_source: "57 FR 61992, Dec. 29, 1992, unless otherwise noted."
cfr_part: "63"
---


# 63.5285 Am I subject to this subpart?

(a) You are subject to this subpart if you own or operate a leather finishing operation that is a major source of hazardous air pollutants (HAP) emissions or that is located at, or is part of, a major source of HAP emissions. A leather finishing operation is defined in § 63.5460. In general, a leather finishing operation is a single process or group of processes used to adjust and improve the physical and aesthetic characteristics of the leather surface through multistage application of a coating comprised of dyes, pigments, film-forming materials, and performance modifiers dissolved or suspended in liquid carriers.

(b) You are a major source of HAP emissions if you own or operate a plant site that emits or has the potential to emit any single HAP at a rate of 10 tons (9.07 megagrams) or more per year or any combination of HAP at a rate of 25 tons (22.68 megagrams) or more per year.

(c) You are not subject to this subpart if your source finishes leather solely for the purpose of research and development.