(a) Except as provided in paragraph (c) 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.
(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) Is sufficiently cleaned of residue and purged of vapors to remove any potential hazard;
(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) 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.
(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) A portable tank having a capacity of less than 3,785 L (1000 gallons);
(2) A DOT 106 or 110 multi-unit tank car tank;
(3) A bulk packaging other than a portable tank, cargo tank, or tank car (e.g., a bulk bag or box) with a volumetric capacity of less than 18 cubic meters (640 cubic feet);
(4)An IBC. For an IBC labeled in accordance with subpart E of this part instead of placarded, the IBC may display the proper shipping name and UN identification number in accordance with the size requirements of § 172.302(b)(2) in place of the UN number on an orange panel or placard.
(5) A Large Packaging as defined in § 171.8 of this subchapter.