For a hazardous-material shipment in non-bulk packages, where must the material’s identification number appear?
Correct answer: C – On the shipping paper and on the package
Federal hazardous-materials rules require the identification number in the material’s shipping-paper description. A non-bulk package generally must also be marked with the proper shipping name and its UN, NA, or ID identification number. Bulk packagings, including cargo tanks, are subject to separate identification-number display requirements.
Source: 49 CFR § 172.202 – Description of hazardous material on shipping papers, 49 CFR § 172.301 – General marking requirements for non-bulk packagings, 49 CFR § 172.302 – General marking requirements for bulk packagings

