# 172.336 Identification numbers; special provisions.
(a) When not required or prohibited by this subpart, identification numbers may be displayed on a transport vehicle or a freight container in the manner prescribed by this subpart.
(b) Identification numbers, when required, must be displayed on either orange panels (see § 172.332(b)) or on a plain white square-on-point display configuration having the same outside dimensions as a placard. In addition, for materials in hazard classes for which placards are specified and identification number displays are required, but for which identification numbers may not be displayed on the placards authorized for the material (see § 172.334(a)), identification numbers must be displayed on orange panels or on the plain white square-on-point display configuration in association with the required placards. An identification number displayed on a white square-on-point display configuration is not considered to be a placard.
(1) The 100 mm (3.9 inch) by 215 mm (8.5 inches) area containing the identification number shall be located as prescribed by § 172.332 (c)(1) and (c)(2) and may be outlined with a solid or dotted line border.
(2) [Reserved]
(c) Identification Numbers are not required:
Table 1 to Paragraph **(c)**—Identification Numbers Are Not Required
| Packaging: | When: | Then the alternative marking requirement is: |
| --- | --- | --- |
| On the ends of portable tanks, cargo tanks, or tank cars | They have more than one compartment and hazardous materials with different identification numbers are being transported therein | The identification numbers on the sides of the tank are displayed in the same sequence as the compartments containing the materials they identify. |
| On cargo tanks | They contain only gasoline | The tank is marked “Gasoline” on each side and rear in letters no less than 50 mm (2 inches) high or is placarded in accordance with § 172.542(c). |
| On cargo tanks | They contain only fuel oil | The cargo tank is marked “Fuel Oil” on each side and rear in letters no less than 50 mm (2 inches) high, or is placarded in accordance with § 172.544(c). |
| On one end of nurse tanks if that end contains valves, fittings, regulators, or gauges when those appurtenances prevent the markings and placard from being properly placed and visible | They meet the provisions of § 173.315(m) of this subchapter | N/A. |
| On each compartment of compartmented cargo tanks or compartmented tank cars | The cargo tank or tank car contains more than one petroleum distillate fuel | The identification number for the liquid petroleum distillate fuel having the lowest flash point in any one compartment is displayed. However, if a cargo tank or tank car compartment contains gasoline and alcohol fuel blends consisting of more than 10% ethanol the identification number “3475” or “1987,” as appropriate, must also be displayed for that compartment. |
| On cargo tanks (including compartmented cargo tanks) | They transport more than one petroleum distillate fuel in different trips on the previous or current business day | The identification number for the liquid petroleum distillate fuel having the lowest flash point transported in that previous or current business day is displayed. If the cargo tank contains gasoline and alcohol fuel blends consisting of more than 10% ethanol, the identification number, “3475” or “1987,” as appropriate, must also be displayed, and the identification numbers “3475” or “1987,” may only be displayed if the material is present in the cargo tank during transportation. |
[Amdt. 172-101, 45 FR 74667, Nov. 10, 1980, as amended by Amdt. 172-74, 47 FR 40365, Sept. 30, 1982; Amdt. 172-109, 52 FR 13038, Apr. 20, 1987; Amdt. 172-110, 52 FR 29528, Aug. 10, 1987; Amdt. 172-123, 55 FR 52593, Dec. 21, 1990; 56 FR 66255, Dec. 20, 1991; 65 FR 50459, Aug. 18, 2000; 73 FR 4716, Jan. 28, 2008; 76 FR 43527, July 20, 2011; 78 FR 14714, Mar. 7, 2013; 78 FR 65478, Oct. 31, 2013; 91 FR 1446, Jan. 14, 2026]