---
kind: "unit"
title: "40"
title_heading: "Protection of Environment"
key: "chI/subchC/part63/subpartZZZZ"
level: "subpart"
label: "Subpart ZZZZ"
heading: "National Emissions Standards for Hazardous Air Pollutants for Stationary Reciprocating Internal Combustion Engines"
release: "ecfr-current"
date: "2026-08-27"
url: "https://uscodex.org/cfr/40/chI-subchC-part63-subpartZZZZ"
sections_count: 26
---

# Subpart ZZZZ — National Emissions Standards for Hazardous Air Pollutants for Stationary Reciprocating Internal Combustion Engines

Title 40 C.F.R. — Protection of Environment › Chapter I — Environmental Protection Agency › Subchapter C — Air Programs › Part 63 — National Emission Standards for Hazardous Air Pollutants for Source Categories

## Sections

- [§63.6580. What is the purpose of subpart ZZZZ?](/cfr/40/63.6580.md)
- [§63.6585. Am I subject to this subpart?](/cfr/40/63.6585.md)
- [§63.6590. What parts of my plant does this subpart cover?](/cfr/40/63.6590.md)
- [§63.6595. When do I have to comply with this subpart?](/cfr/40/63.6595.md)
- [§63.6600. What emission limitations and operating limitations must I meet if I own or operate a stationary RICE with a site rating of more than 500 brake HP located at a major source of HAP emissions?](/cfr/40/63.6600.md)
- [§63.6601. What emission limitations must I meet if I own or operate a new or reconstructed 4SLB stationary RICE with a site rating of greater than or equal to 250 brake HP and less than or equal to 500 brake HP located at a major source of HAP emissions?](/cfr/40/63.6601.md)
- [§63.6602. What emission limitations and other requirements must I meet if I own or operate an existing stationary RICE with a site rating of equal to or less than 500 brake HP located at a major source of HAP emissions?](/cfr/40/63.6602.md)
- [§63.6603. What emission limitations, operating limitations, and other requirements must I meet if I own or operate an existing stationary RICE located at an area source of HAP emissions?](/cfr/40/63.6603.md)
- [§63.6604. What fuel requirements must I meet if I own or operate a stationary CI RICE?](/cfr/40/63.6604.md)
- [§63.6605. What are my general requirements for complying with this subpart?](/cfr/40/63.6605.md)
- [§63.6610. By what date must I conduct the initial performance tests or other initial compliance demonstrations if I own or operate a stationary RICE with a site rating of more than 500 brake HP located at a major source of HAP emissions?](/cfr/40/63.6610.md)
- [§63.6611. By what date must I conduct the initial performance tests or other initial compliance demonstrations if I own or operate a new or reconstructed 4SLB SI stationary RICE with a site rating of greater than or equal to 250 and less than or equal to 500 brake HP located at a major source of HAP emissions?](/cfr/40/63.6611.md)
- [§63.6612. By what date must I conduct the initial performance tests or other initial compliance demonstrations if I own or operate an existing stationary RICE with a site rating of less than or equal to 500 brake HP located at a major source of HAP emissions or an existing stationary RICE located at an area source of HAP emissions?](/cfr/40/63.6612.md)
- [§63.6615. When must I conduct subsequent performance tests?](/cfr/40/63.6615.md)
- [§63.6620. What performance tests and other procedures must I use?](/cfr/40/63.6620.md)
- [§63.6625. What are my monitoring, installation, collection, operation, and maintenance requirements?](/cfr/40/63.6625.md)
- [§63.6630. How do I demonstrate initial compliance with the emission limitations, operating limitations, and other requirements?](/cfr/40/63.6630.md)
- [§63.6635. How do I monitor and collect data to demonstrate continuous compliance?](/cfr/40/63.6635.md)
- [§63.6640. How do I demonstrate continuous compliance with the emission limitations, operating limitations, and other requirements?](/cfr/40/63.6640.md)
- [§63.6645. What notifications must I submit and when?](/cfr/40/63.6645.md)
- [§63.6650. What reports must I submit and when?](/cfr/40/63.6650.md)
- [§63.6655. What records must I keep?](/cfr/40/63.6655.md)
- [§63.6660. In what form and how long must I keep my records?](/cfr/40/63.6660.md)
- [§63.6665. What parts of the General Provisions apply to me?](/cfr/40/63.6665.md)
- [§63.6670. Who implements and enforces this subpart?](/cfr/40/63.6670.md)
- [§63.6675. What definitions apply to this subpart?](/cfr/40/63.6675.md)