# Class 9—Definitions.

- **operation:** document
- **citation:** 49 CFR 173.140
- **title:** Class 9—Definitions.
- **source type:** regulation
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** current
- **official:** true
- **published on:** Not available
- **effective on:** 2026-08-18
- **summary:** For the purposes of this subchapter, miscellaneous hazardous material (Class 9) means a material which presents a hazard during transportation but which does not meet the definition of any other hazard class. This class includes:

(a) Any material which has an anesthetic, noxious or other similar pr
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- **markdown:** https://regulus.evalyn.ai/document/49-cfr-173-140.md
- **app url:** https://regulus.evalyn.ai/document/49-cfr-173-140
- **source url:** https://www.ecfr.gov/on/2026-08-18/title-49/section-173.140
**body:**

For the purposes of this subchapter, miscellaneous hazardous material (Class 9) means a material which presents a hazard during transportation but which does not meet the definition of any other hazard class. This class includes:

(a) Any material which has an anesthetic, noxious or other similar property which could cause extreme annoyance or discomfort to a flight crew member so as to prevent the correct performance of assigned duties; or

(b) Any material that meets the definition in § 171.8 of this subchapter for an elevated temperature material, a hazardous substance, a hazardous waste, or a marine pollutant.

[Amdt. 173-224, 57 FR 45463, Oct. 1, 1992, as amended by Amdt. 173-231, 57 FR 52939, Nov. 5, 1992; Amdt. 173-233, 58 FR 33305, June 16, 1993]
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