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Section §173.320: Cryogenic liquids; exceptions

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Additionally PHMSA has Hazardous Materials FAQs based on letters of interpretation on the following topics:

This section of the website provides the ability to find regulations information including regulations parts, content of sections, and interpretations for regulations sections. Below is a list of parts, identified by the part number and subject. To browse sections by part, click on the subject link below. You will be taken to the eCFR website to view sections for a part.

A written regulatory interpretation, response to a question, or an opinion concerning a pipeline safety issue may be obtained by submitting a written request to the Office of Pipeline Safety (PHP–30), PHMSA, U.S. Department of Transportation, 1200 New Jersey Avenue SE., Washington, DC 20590–0001 or at the email address: In addition to email address, the requestor must include his or her return address and should also include a daytime telephone number. Requests should be submitted at least 120 days before the time the requestor needs a response.

Note: electronic submission is provided as alternative to the 49 CFR Part 190.11(b) mail-in requirement.

The regulations text of the section can be found on the eCFR website. To view the regulations text, use the link below. For assistance, please send an email to

View section 173.320 on the ECFR website

Interpretation Responses

Ref ID Date Company Name Individual Name Response Document
24-0007 ABC Nitrogen Service Corp Aimee Fontenot View
22-0129 American Bureau of Shipping Ms. Simone Goncalves View
20-0050 Fisher BioServices Aijaz A. Khan View
19-0066 Cryogenic Services, Ltd. Connor Orban View
18-0025 FHP-CVE West Palm Beach Office Sergeant Steve L. Brown View
11-0144 Chart Industries, Inc. Mr. Marty Beyer View
08-0060 Cryogenic Equipment and Services, LLC Mr. John D. Upperman View
12-0105 Arcet Cylinder Services Div. Mr. David Goff View
11-0046 Chart Industries Mr. Dan Bricker View
99-0278 Condon & Forsyth, LLP Mr. David F. Rifkind View
13-0196 Select Sire Power, Inc. Mr. Mark Carpenter View
13-0209 DuPont Global Logistics Mr. Kevin Greene View
14-0203 The Cryo Guys Mr. Mike Tomasek View
10-0210 Cryofab, Inc. Mr. Greg Grillo View
10-0079 Air Liquide Industrial U.S. LP Mr. Steven Bilger View
01-0038 William Wilkening View
10-0101 Jefferson Lab Thomas Jefferson National Accelerator Facility Mr. Thomas Briggs, PE View
99-0056 Radian International Mr. Andrew N. Romach View
08-0289 Durham, Jones & Pinegar, P.C. Mr. Michael F. Leavitt View