# Rules of regulatory construction.

- **operation:** document
- **citation:** 49 CFR 193.2009
- **title:** Rules of regulatory construction.
- **source type:** regulation
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** current
- **official:** true
- **published on:** Not available
- **effective on:** 2026-08-18
- **summary:** (a) As used in this part:

(1) Includes means including but not limited to;

(2) May means is permitted to or is authorized to;

(3) May not means is not permitted to or is not authorized to; and

(4) Shall or must is used in the mandatory and imperative sense.

(b) In this part:

(1) Words importin
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- **markdown:** https://regulus.evalyn.ai/document/49-cfr-193-2009.md
- **app url:** https://regulus.evalyn.ai/document/49-cfr-193-2009
- **source url:** https://www.ecfr.gov/on/2026-08-18/title-49/section-193.2009
**body:**

(a) As used in this part:

(1) Includes means including but not limited to;

(2) May means is permitted to or is authorized to;

(3) May not means is not permitted to or is not authorized to; and

(4) Shall or must is used in the mandatory and imperative sense.

(b) In this part:

(1) Words importing the singular include the plural; and

(2) Words importing the plural include the singular.
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- **body characters:** 392