49 CFR §172.400a

1. (a)Notwithstanding the provisions of § 172.400, a label is not required on—
   1. (1)A Dewar flask meeting the requirements in § 173.320 of this subchapter or a cylinder containing a Division 2.1, 2.2, or 2.3 material that is durably and legibly marked in accordance with CGA C-7, Appendix A (IBR; see § 171.7 of this subchapter). Notwithstanding this exception, overpacks must be labeled (see § 173.25 of this subchapter).
   2. (2)A package or unit of military explosives (including ammunition) shipped by or on behalf of the DOD when in—
      1. (i)Freight containerload, carload or truckload shipments, if loaded and unloaded by the shipper or DOD; or
      2. (ii)Unitized or palletized break-bulk shipments by cargo vessel under charter to DOD if at least one required label is displayed on each unitized or palletized load.
   3. (3)A package containing a hazardous material other than ammunition that is—
      1. (i)Loaded and unloaded under the supervision of DOD personnel, and
      2. (ii)Escorted by DOD personnel in a separate vehicle.
   4. (4)A compressed gas cylinder permanently mounted in or on a transport vehicle.
   5. (5)A freight container, aircraft unit load device or portable tank, which—
      1. (i)Is placarded in accordance with subpart F of this part, or
      2. (ii)Conforms to paragraph (a)(3) or (b)(3) of § 172.512.
   6. (6)An overpack or unit load device in or on which labels representative of each hazardous material in the overpack or unit load device are visible.
   7. (7)A package of low specific activity radioactive material and surface contaminated objects, when transported under § 173.427(a)(6)(vi) of this subchapter.
   8. (8)Packages containing toy plastic or paper caps for toy pistols described as “UN0349, Articles, explosive, n.o.s. (Toy caps), 1.4S” or “NA0337, Toy caps, 1.4S” when offered in conformance with the conditions of § 172.102(c)(1), Special provision 382.
2. (b)Certain exceptions to labeling requirements are provided for small quantities and limited quantities in applicable sections in part 173 of this subchapter.
3. (c)Notwithstanding the provisions of § 172.402(a), a Division 6.1 subsidiary hazard label is not required on a package containing a Class 8 (corrosive) material which has a subsidiary hazard of Division 6.1 (poisonous) if the toxicity of the material is based solely on the corrosive destruction of tissue rather than systemic poisoning. In addition, a Division 4.1 subsidiary hazard label is not required on a package bearing a Division 4.2 label.
4. (d)A package containing a material poisonous by inhalation (see § 171.8 of this subchapter) in a closed transport vehicle or freight container may be excepted from the POISON INHALATION HAZARD or POISON GAS label or placard, under the conditions set forth in § 171.23(b)(10) of this subchapter.