Applicability of Placarding Requirements to Cylinders
Pipeline and Hazardous Materials Safety Administration · Jan 24, 2006 · Reference No. 06-0004
Interprets: 49 CFR § 172.504(c)
Reggie’s quick take
A shipper asked whether the placarding exception in § 172.504(c) for less than 1,001 pounds of Table 2 materials covers Division 2.2 gases in cylinders. The cylinders are on one vehicle and weigh about 4,800 pounds in total. PHMSA said no. The exception counts the gross weight of all non-bulk packages on the vehicle, meaning the packages plus their contents. At about 4,800 pounds, the vehicle must be placarded.
Written by AI (Claude) on Oct 22, 2026. Robots make mistakes and leave things out, so the letter below is what counts. Not legal advice.
This is in response to your letter requesting clarification of the placarding requirements under the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). Specifically, you ask if the exception from placarding in § 172.504(c), for less than 454 kg (1001 pounds) aggregate gross weight of hazardous materials covered by Table 2 of 172.504(e), applies to the Division 2.2 material in cylinders. You indicate that the cylinders are loaded on a single transport vehicle and weigh approximately 4,800 pounds.
The placarding exception in § 172.504(c) applies to the aggregate gross weight of all non- bulk packagings on a single transport vehicle that are covered by Table 2 of § 172.504(e) and do not fall under the provisions of 172.505. As defined in § 171.8, the phrase "gross weight" is the weight of a packaging plus the weight of its contents. In your scenario, the aggregate gross weight is equivalent to the aggregate weight of all cylinders and the Division 2.2 material they contain. Therefore, given that the aggregate gross weight of your cylinders is approximately 4,800 pounds, the transport vehicle must be placarded.
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.