Interpretation Response #26-0004
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Carbotainer S.L.
Individual Name: Guillermo Garcia Andreu
View the Interpretation Document
Response text:
March 17, 2026
Guillermo Garcia Andreu
Industrial, Technical and Production Director
Carbotainer S.L.
C/Buenos Aires, Nº4 Pol. Ind. Centrovía
50196 LA MUELA (Zaragoza) Spain
Reference No. 26-0004
Dear Mr. Garcia Andreu:
This letter is in response to your December 16, 2025 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the use of United Nations (UN) pressure receptacles (i.e., refillable composite cylinders) meeting International organization for Standardization (ISO) 11119-2 specification standards, approved under the Transport Canada Transportation of Dangerous Goods (TDG) Regulations and marked with "CAN" to indicate Canada as the country of approval.
We have paraphrased and answered your questions as follows:
Q1. May these refillable composite cylinders, approved and marked as described above, be used to transport hazardous materials within the United States by highway, rail, air, and vessel?
A1. Yes. Section 171.12(a)(4) provides that when the HMR require that a Department of Transportation (DOT) specification or a UN pressure receptacle must be used for a hazardous material, a packaging authorized by the Transport Canada TDG Regulations may also be used if it corresponds to the DOT specification or UN standard authorized by the HMR. By incorporating ISO 11119-2:2012/Amd.1:2014(E) into § 171.7 of the HMR, PHMSA authorizes composite cylinders designed to meet this standard.
Q2. May ISO 11119-2 refillable composite cylinders approved by Transport Canada be offered for sale and placed into commerce in the United States?
A2. Yes. See answer A1.
Q3. May ISO 11119-2 refillable composite cylinders, including cylinders conforming to valve protection standards in ISO 11117, be filled within the United States in accordance with the HMR instead of Transport Canada TDG Regulations?
A3. Yes. Canadian approved UN specification cylinders may be filled within the United States in accordance with the requirements of the HMR instead of Transport Canada TDR regulations. Note that valves are subject to the protection requirements in § 173.301b(c).
Q4. May an organization that has a Requalification Identification Number (RIN) issued by the United States DOT requalify these cylinders?
A4. Yes, provided that the scope of the requalification facility RIN approval includes performing requalification of Transport Canada-approved ISO 11119-2 pressure receptacles. UN cylinders with a country of approval of the United States or Canada must be tested in accordance with the test requirements in § 180.207, which specifies requirements for the requalification of UN pressure receptacles.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division