49 CFR §172.200

1. (a)Description of hazardous materials required. Except as otherwise provided in this subpart, each person who offers a hazardous material for transportation shall describe the hazardous material on the shipping paper in the manner required by this subpart.
2. (b)This subpart does not apply to any material, other than a hazardous substance, hazardous waste or marine pollutant, that is—
   1. (1)Identified by the letter “A” in column 1 of the § 172.101 table, except when the material is offered or intended for transportation by air; or
   2. (2)Identified by the letter “W” in column 1 of the § 172.101 table, except when the material is offered or intended for transportation by water; or
   3. (3)A limited quantity package unless the material is offered for transportation by aircraft or vessel.
   4. (4)Category B infectious substances prepared in accordance with § 173.199.