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Title 40

Displaying title 40, up to date as of 7/08/2026. Title 40 was last amended 7/08/2026.
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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 DDDDD   View Full Text
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eCFR Content

The Code of Federal Regulations (CFR) is the official legal print publication containing the codification of the general and permanent rules published in the Federal Register by the departments and agencies of the Federal Government. The Electronic Code of Federal Regulations (eCFR) is a continuously updated online version of the CFR. It is not an official legal edition of the CFR.

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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 DDDDDNational Emission Standards for Hazardous Air Pollutants for Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters63.7480 – 63.7575
What This Subpart Covers63.7480 – 63.7495
§ 63.7480What is the purpose of this subpart?
§ 63.7485Am I subject to this subpart?
§ 63.7490What is the affected source of this subpart?
§ 63.7491Are any boilers or process heaters not subject to this subpart?
§ 63.7495When do I have to comply with this subpart?
Emission Limitations and Work Practice Standards63.7499 – 63.7501
§ 63.7499What are the subcategories of boilers and process heaters?
§ 63.7500What emission limitations, work practice standards, and operating limits must I meet?
§ 63.7501 [Reserved]
General Compliance Requirements63.7505
§ 63.7505What are my general requirements for complying with this subpart?
Testing, Fuel Analyses, and Initial Compliance Requirements63.7510 – 63.7533
§ 63.7510What are my initial compliance requirements and by what date must I conduct them?
§ 63.7515When must I conduct subsequent performance tests, fuel analyses, or tune-ups?
§ 63.7520What stack tests and procedures must I use?
§ 63.7521What fuel analyses, fuel specification, and procedures must I use?
§ 63.7522Can I use emissions averaging to comply with this subpart?
§ 63.7525What are my monitoring, installation, operation, and maintenance requirements?
§ 63.7530How do I demonstrate initial compliance with the emission limitations, fuel specifications and work practice standards?
§ 63.7533Can I use efficiency credits earned from implementation of energy conservation measures to comply with this subpart?
Continuous Compliance Requirements63.7535 – 63.7541
§ 63.7535Is there a minimum amount of monitoring data I must obtain?
§ 63.7540How do I demonstrate continuous compliance with the emission limitations, fuel specifications and work practice standards?
§ 63.7541How do I demonstrate continuous compliance under the emissions averaging provision?
Notification, Reports, and Records63.7545 – 63.7560
§ 63.7545What notifications must I submit and when?
§ 63.7550What reports must I submit and when?
§ 63.7555What records must I keep?
§ 63.7560In what form and how long must I keep my records?
Other Requirements and Information63.7565 – 63.7575
§ 63.7565What parts of the General Provisions apply to me?
§ 63.7570Who implements and enforces this subpart?
§ 63.7575What definitions apply to this subpart?
Table 1 to Subpart DDDDD of Part 63
Emission Limits for New or Reconstructed Boilers and Process Heaters c
Table 2 to Subpart DDDDD of Part 63
Emission Limits for Existing Boilers and Process Heaters d
Table 3 to Subpart DDDDD of Part 63
Work Practice Standards
Table 4 to Subpart DDDDD of Part 63
Operating Limits for Boilers and Process Heaters
Table 5 to Subpart DDDDD of Part 63
Performance Testing Requirements
Table 6 to Subpart DDDDD of Part 63
Fuel Analysis Requirements
Table 7 to Subpart DDDDD of Part 63
Establishing Operating Limits a b
Table 8 to Subpart DDDDD of Part 63
Demonstrating Continuous Compliance
Table 9 to Subpart DDDDD of Part 63
Reporting Requirements
Table 10 to Subpart DDDDD of Part 63
Applicability of General Provisions to Subpart DDDDD
Table 11 to Subpart DDDDD of Part 63
Alternative Emission Limits for New or Reconstructed Boilers and Process Heaters That Commenced Construction or Reconstruction After June 4, 2010, and Before May 20, 2011
Table 12 to Subpart DDDDD of Part 63
Alternative Emission Limits for New or Reconstructed Boilers and Process Heaters That Commenced Construction or Reconstruction After May 20, 2011, and Before December 23, 2011
Table 13 to Subpart DDDDD of Part 63
Alternative Emission Limits for New or Reconstructed Boilers and Process Heaters That Commenced Construction or Reconstruction After December 23, 2011, and Before April 1, 2013
Table 14 to Subpart DDDDD of Part 63
Alternative Emission Limits for New or Reconstructed Boilers and Process Heaters c
Table 15 to Subpart DDDDD of Part 63
Alternative Emission Limits for Existing Boilers and Process Heaters d
eCFR Content