1. (a) Subsidiary hazard labels. Each package containing a hazardous material—

   1. (1) Shall be labeled with primary and subsidiary hazard labels as specified in column 6 of the § 172.101 table (unless excepted in paragraph (a)(2) of this section); and

   2. (2) For other than Class 1 or Class 2 materials (for subsidiary labeling requirements for Class 1 or Class 2 materials see paragraph (e) or paragraphs (f) and (g), respectively, of this section), if not already labeled under paragraph (a)(1) of this section, shall be labeled with subsidiary hazard labels in accordance with the following table:

      Subsidiary Hazard Labels

      Subsidiary hazard level (packing group)	Subsidiary Hazard (Class or Division)
      3	4.1	4.2	4.3	5.1	6.1	8
      I	X	***	***	X	X	X	X
      II	X	X	X	X	X	X	X
      III	*	X	X	X	X	X	X
      X—Required for all modes.
      *—Required for all modes, except for a material with a flash point at or above 38 °C (100 °F) transported by rail or highway.
      **—Reserved
      ***—Impossible as subsidiary hazard.

2. (b) Display of hazard class on labels. The appropriate hazard class or division number must be displayed in the lower corner of a primary hazard label and a subsidiary hazard label.
3. (c) Cargo Aircraft Only label. Each person who offers for transportation or transports by aircraft a package containing a hazardous material which is authorized on cargo aircraft only shall label the package with a CARGO AIRCRAFT ONLY label specified in § 172.448 of this subpart.

4. (d) Class 7 (Radioactive) Materials. Except as otherwise provided in this paragraph, each package containing a Class 7 material that also meets the definition of one or more additional hazard classes must be labeled as a Class 7 material as required by § 172.403 and for each additional hazard.

   1. (1) A subsidiary label is not required for a package containing material that satisfies all of the criteria in § 173.4, § 173.4a, or § 173.4b applicable to the subsidiary hazard class.
   2. (2) Each package or overpack containing fissile material, other than fissile-excepted material (see § 173.453 of this subchapter) must bear two FISSILE labels, affixed to opposite sides of the package or overpack, which conforms to the figure shown in § 172.441; such labels, where applicable, must be affixed adjacent to the labels for radioactive materials.

5. (e) Class 1 (explosive) Materials. In addition to the label specified in column 6 of the § 172.101 table, each package of Class 1 material that also meets the definition for:

   1. (1) Division 6.1, Packing Groups I or II, shall be labeled POISON or POISON INHALATION HAZARD, as appropriate.
   2. (2) Class 7, shall be labeled in accordance with § 172.403 of this subpart.
6. (f) Division 2.2 materials. In addition to the label specified in column 6 of the § 172.101 table, each package of Division 2.2 material that also meets the definition for an oxidizing gas (see § 171.8 of this subchapter) must be labeled OXIDIZER.

7. (g) Division 2.3 materials. In addition to the label specified in column 6 of the § 172.101 table, each package of Division 2.3 material that also meets the definition for:

   1. (1) Division 2.1, must be labeled Flammable Gas;
   2. (2) Division 5.1, must be labeled Oxidizer; and
   3. (3) Class 8, must be labeled Corrosive.

[Amdt. 172-123, 55 FR 52594, Dec. 21, 1990, as amended at 56 FR 66255, Dec. 20, 1991; Amdt. 172-139, 59 FR 67490, Dec. 29, 1994; Amdt. 172-140, 60 FR 26805, May 18, 1995; Amdt. 172-149, 61 FR 27173, May 30, 1996; 62 FR 39405, July 22, 1997; 66 FR 33425, June 21, 2001; 69 FR 3668, Jan. 26, 2004; 74 FR 2252, Jan. 14, 2009; 76 FR 56314, Sept. 13, 2011; 79 FR 40609, July 11, 2014]