---
kind: "section"
citation: "40 C.F.R. § 63.3"
title: "40"
number: "63.3"
heading: "Units and abbreviations."
url: "https://uscodex.org/cfr/40/63.3"
---

# §63.3. Units and abbreviations.


Used in this part are abbreviations and symbols of units of measure. These are defined as follows:

- (a) **System International (SI) units of measure—**
- (b) **Other units of measure—**
- (c) **Miscellaneous—**

## Notes

### Amendments

[59 FR 12430, Mar. 16, 1994, as amended at 67 FR 16598, Apr. 5, 2002]

### Source

Source: 59 FR 12430, Mar. 16, 1994, unless otherwise noted.

### Authority

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

### Source

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

### Amendments

[59 FR 12430, Mar. 16, 1994, as amended at 67 FR 16598, Apr. 5, 2002]