---
kind: "section"
citation: "40 C.F.R. § 63.11503"
title: "40"
number: "63.11503"
heading: "Who implements and enforces this subpart?"
url: "https://uscodex.org/cfr/40/63.11503"
---

# §63.11503. Who implements and enforces this subpart?

- (a) This subpart can be implemented and enforced by the U.S. EPA or a delegated authority such as a State, local, or tribal agency. If the U.S. EPA Administrator has delegated authority to a State, local, or tribal agency pursuant to [40 CFR part 63](/cfr/40/part63.md), [subpart E](/cfr/40/subpartE.md), then that Agency has the authority to implement and enforce this subpart. You should contact your U.S. EPA Regional Office to find out if this subpart is delegated to a State, local, or tribal agency within your State.
- (b) In delegating implementation and enforcement authority of this subpart to a State, local, or Tribal agency under [subpart E](/cfr/40/subpartE.md) of this part, the approval authorities contained in [paragraphs (b)(1) through (5)](#b-1..b-5) of this section are retained by the Administrator of the U.S. EPA and are not transferred to the state, local, or Tribal agency.
  - (1) Approval of an alternative non-opacity emissions standard under [§ 63.6(g)](/cfr/40/63.6.md?p=g).
  - (2) **Approval of a major change to a test method.** A “major change to test method” is defined in [§ 63.90](/cfr/40/63.90.md).
  - (3) Approval of a major change to monitoring under [§ 63.8(f)](/cfr/40/63.8.md?p=f). A “major change to monitoring” is defined in [§ 63.90](/cfr/40/63.90.md).
  - (4) Approval of a major change to recordkeeping/reporting under [§ 63.10(f)](/cfr/40/63.10.md?p=f). A “major change to recordkeeping/reporting” is defined in [§ 63.90](/cfr/40/63.90.md).
  - (5) **Approval of an alternative to any electronic reporting to the EPA required by this subpart.**

## Notes

### Amendments

[74 FR 56041, Oct. 29, 2009, as amended at 91 FR 16533, Apr. 1, 2026]

### Source

Source: 74 FR 56041, Oct. 29, 2009, unless otherwise noted.

### Authority

Authority: 42 U.S.C. 7401 et seq.

### Source

Source: 57 FR 61992, Dec. 29, 1992, unless otherwise noted.

### Amendments

[74 FR 56041, Oct. 29, 2009, as amended at 91 FR 16533, Apr. 1, 2026]