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Title 40

Displaying title 40, up to date as of 7/16/2026. Title 40 was last amended 7/16/2026.
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  1. Title 40 —Protection of Environment
  2. Chapter I —Environmental Protection Agency
  3. Subchapter C —Air Programs
  4. Part 63 —National Emission Standards for Hazardous Air Pollutants for Source Categories
  5. Subpart TTTT   View Full Text
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eCFR Content

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Title 40Protection of EnvironmentPart / Section
Chapter IEnvironmental Protection Agency1 – 1099
Subchapter CAir Programs50 – 99
Part 63National Emission Standards for Hazardous Air Pollutants for Source Categories63.1 – 63.12099
Subpart TTTTNational Emission Standards for Hazardous Air Pollutants for Leather Finishing Operations63.5280 – 63.5460
What This Subpart Covers63.5280 – 63.5295
§ 63.5280What is the purpose of this subpart?
§ 63.5285Am I subject to this subpart?
§ 63.5290What parts of my facility does this subpart cover?
§ 63.5295When do I have to comply with this subpart?
Standards63.5305
§ 63.5305What emission standards must I meet?
Compliance Requirements63.5320 – 63.5360
§ 63.5320How does my affected major source comply with the HAP emission standards?
§ 63.5325What is a plan for demonstrating compliance and when must I have one in place?
§ 63.5330How do I determine the compliance ratio?
§ 63.5335How do I determine the actual HAP loss?
§ 63.5340How do I determine the allowable HAP loss?
§ 63.5345How do I distinguish between the two upholstery product process operations?
§ 63.5350How do I distinguish between the water-resistant/specialty and nonwater-resistant leather product process operations?
§ 63.5355How do I monitor and collect data to demonstrate continuous compliance?
§ 63.5360How do I demonstrate continuous compliance with the emission standards?
Testing and Initial Compliance Requirements63.5375 – 63.5400
§ 63.5375When must I conduct a performance test or initial compliance demonstration?
§ 63.5380How do I conduct performance tests?
§ 63.5385How do I measure the quantity of finish applied to the leather?
§ 63.5390How do I measure the HAP content of a finish?
§ 63.5395How do I measure the density of a finish?
§ 63.5400How do I measure the quantity of leather processed?
Notifications, Reports, and Records63.5415 – 63.5435
§ 63.5415What notifications must I submit and when?
§ 63.5420What reports must I submit and when?
§ 63.5425When must I start recordkeeping to determine my compliance ratio?
§ 63.5430What records must I keep?
§ 63.5435In what form and how long must I keep my records?
Other Requirements and Information63.5450 – 63.5460
§ 63.5450What parts of the General Provisions apply to me?
§ 63.5455Who administers this subpart?
§ 63.5460What definitions apply to this subpart?
Figure 1 to Subpart TTTT of Part 63
Example Logs for Recording Leather Finish Use and HAP Content
Table 1 to Subpart TTTT of Part 63
Leather Finishing HAP Emission Limits for Determining the Allowable HAP Loss
Table 2 to Subpart TTTT of Part 63
Applicability of General Provisions to Subpart TTTT
eCFR Content