49 CFR §172.514

1. (a)Except as provided in paragraphs (c) and (d) of this section, each person who offers for transportation a bulk packaging which contains a hazardous material, shall affix the placards specified for the material in §§ 172.504 and 172.505.
2. (b)Each bulk packaging that is required to be placarded when it contains a hazardous material, must remain placarded when it is emptied, unless it—
   1. (1)Is sufficiently cleaned of residue and purged of vapors to remove any potential hazard;
   2. (2)Is refilled, with a material requiring different placards or no placards, to such an extent that any residue remaining in the packaging is no longer hazardous; or
   3. (3)Contains the residue of a hazardous substance in Class 9 in a quantity less than the reportable quantity, and conforms to § 173.29(b)(1) of this subchapter.
3. (c)Exceptions. The following packagings may be placarded on only two opposite sides or, alternatively, may be labeled instead of placarded in accordance with subpart E of this part:
   1. (1)A portable tank having a capacity of less than 3,785 L (1,000 gallons). Additionally, portable tanks containing a combustible liquid may be placarded with a combustible placard that meets the label specifications for size in § 172.407(c). However, a transport vehicle containing portable tanks with a reduced-size combustible placard is still required to conform to the placarding requirements in this subpart, including the size requirements in § 172.519(c);
   2. (2)A DOT 106 or 110 multi-unit tank car tank;
   3. (3)A bulk packaging other than a portable tank, cargo tank, flexible bulk container, or tank car (e.g., a bulk bag or box) with a volumetric capacity of less than 18 cubic meters (640 cubic feet);
   4. (4)For an intermediate bulk container (IBC) labeled in accordance with subpart E of this part, the IBC may display the proper shipping name and UN identification number markings in accordance with § 172.301(a)(1) in place of the UN number on an orange panel, placard, or white square-on-point configuration as prescribed in § 172.336(d). Additionally, IBCs containing a combustible liquid may be placarded with a combustible placard that meets the label specifications for size in § 172.407(c). However, a transport vehicle containing IBCs with a reduced-size combustible placard is still required to conform to the placarding requirements in this subpart, including the size requirements in § 172.519(c); and
   5. (5)A Large Packaging as defined in § 171.8 of this subchapter.
4. (d)A flexible bulk container may be placarded in two opposing positions.