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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #10-0183 ([Air Liquide America Specialty Gases LLC] [Mr. Ralph Diaz])

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: Air Liquide America Specialty Gases LLC

Individual Name: Mr. Ralph Diaz

Location State: TX Country: US

View the Interpretation Document

Response text:

December 28, 2010



Mr. Ralph Diaz

Air Liquide America Specialty Gases LLC

2700 Post Oak Blvd., Suite 1800

Houston, TX 77056

Reference No.: 10-0183

Dear Mr. Diaz:

This is in response to your letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the filling of non-DOT, non-UN/ISO compressed gas cylinders for export. Specifically, you ask for verification that the requirement found in

§ 171.23(a)(4)(ii) specifying that non-DOT, non-UN/ISO compressed gas cylinders for export must be equipped with a pressure relief device (PRD) is the intention of the United States Department of Transportation and not an error.

On August 8, 2002, the Research and Special Programs Administration (the predecessor organization to the Pipeline and Hazardous Materials Safety Administration (PHMSA)) issued a final rule under Docket No. HM-220D [67 FR 51625] to amend various requirements related to the maintenance, requalification, use, and repair of DOT specification cylinders. As part of this rulemaking, § 173.301(l) was added and specified the "requirements for filling foreign cylinders for export." As you noted in your incoming letter, as recently as 2003-2004, § 173.301(l) allowed "A cylinder not manufactured, inspected, tested and marked in accordance with part 178 of this subchapter, or a cylinder manufactured to other than a DOT specification or exemption, may be filled with a gas in the United States and offered for transportation and transported for export" under certain conditions, none of which required the cylinder to be equipped with a PRD. On May 3, 2007, PHMSA published a final rule under Docket No. HM-215F [72 FR 25161] which revised and consolidated the requirements applicable to the use of the authorized international standards. As part of this rulemaking, PHMSA moved the cylinder import/export requirements from paragraphs (k) and (l) in § 173.301 to a new § 171.23. These sections were not intended to be modified, only moved from one location in the regulations to a new location. This issue will be addressed in a future rulemaking.

Thank you for identifying this need for clarification and bringing it to our attention.


T. Glenn Foster

Chief, Regulatory Review and Reinvention Branch

Standards and Rulemaking Division

171.23 173.301

Regulation Sections

Section Subject
171.23 Requirements for specific materials and packagings transported under the ICAO Technical Instructions, IMDG Code, Transport Canada TDG Regulations, or the IAEA Regulations
173.301 General requirements for shipment of compressed gases and other hazardous materials in cylinders, UN pressure receptacles and spherical pressure vessels