§ 173.2 Hazardous material classes and index to hazard class definitions.
Current through Sep 25, 2026 · Read all of Part 173
The hazard class of a hazardous material is indicated by either the class or division number or the class name. The following table lists class numbers, division numbers, class or division names and those sections of this subchapter which contain definitions for classifying hazardous materials, including forbidden materials.
Table 1 to § 173.2
| Class No. | Division number (if applicable) | Name of class or division | 49 CFR reference for definitions |
|---|---|---|---|
| None | FORBIDDEN MATERIALS | 173.21 | |
| None | FORBIDDEN EXPLOSIVES | 173.54 | |
| 1 | 1.1 | EXPLOSIVES (WITH A MASS EXPLOSION HAZARD) | 173.50 |
| 1 | 1.2 | EXPLOSIVES (WITH A PROJECTION HAZARD) | 173.50 |
| 1 | 1.3 | EXPLOSIVES (WITH PREDOMINATELY A FIRE HAZARD) | 173.50 |
| 1 | 1.4 | EXPLOSIVES (WITH NO SIGNIFICANT BLAST HAZARD) | 173.50 |
| 1 | 1.5 | VERY INSENSITIVE EXPLOSIVES; BLASTING AGENTS | 173.50 |
| 1 | 1.6 | EXTREMELY INSENSITIVE DETONATING SUBSTANCES | 173.50 |
| 2 | 2.1 | FLAMMABLE GAS | 173.115 |
| 2 | 2.2 | NON-FLAMMABLE COMPRESSED GAS | 173.115 |
| 2 | 2.3 | POISONOUS GAS | 173.115 |
| 3 | FLAMMABLE AND COMBUSTIBLE LIQUID | 173.120 | |
| 4 | 4.1 | FLAMMABLE SOLID | 173.124 |
| 4 | 4.2 | SPONTANEOUSLY COMBUSTIBLE MATERIAL | 173.124 |
| 4 | 4.3 | DANGEROUS WHEN WET MATERIAL | 173.124 |
| 5 | 5.1 | OXIDIZER | 173.127 |
| 5 | 5.2 | ORGANIC PEROXIDE | 173.128 |
| 6 | 6.1 | POISONOUS MATERIALS | 173.132 |
| 6 | 6.2 | INFECTIOUS SUBSTANCE (ETIOLOGIC AGENT) | 173.134 |
| 7 | RADIOACTIVE MATERIAL | 173.403 | |
| 8 | CORROSIVE MATERIAL | 173.136 | |
| 9 | MISCELLANEOUS HAZARDOUS MATERIAL | 173.140 |
[87 FR 79774, Dec. 27, 2022]
Interpretation letters (6)
- Classification of Soda Lime — PHMSA, May 19, 2016
- Requirements Applicable to Non-Spillable Batteries — PHMSA, Jun 26, 2015
- Material meeting the definition of more than one hazard class — PHMSA, Feb 11, 2009
- Biological Samples Preserved with Formalin — PHMSA, Apr 10, 2003
- Samples of Potentially Infectious Substances — PHMSA, Feb 22, 2002
- Multi-hazardous Material for Shipment by Air — PHMSA, Jun 18, 1993