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Section §171.23: Requirements for specific materials and packagings transported under the ICAO Technical Instructions, IMDG Code, Transport Canada TDG Regulations, or the IAEA Regulations

Below are the available interpretations and guidance for the given section. To return to the list of parts, use the Parts link above. If you do not see any guidance or interpretation information below, that means there is none available for the given part/section. Return to the search page to browse additional regulations sections.

PHMSA has published several Frequently Asked Questions (FAQ) documents on regulatory topics. Please review our FAQ documents below:

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 171.23 on the ECFR website

Interpretation Responses

Ref ID Date Company Name Individual Name Response Document
23-0066 W.R. Grace & Co - Conn. Mr. Paul Errichetti View
22-0047 Bureau Veritas Inspection and Insurance Company Edgar A. Whittle View
22-0035 Linde Gas & Equipment Inc. Mike Stephens View
21-0115 Intermodal Tank Transport Jasmine Builes View
21-0062 Institute of Makers of Explosives Susan JP Flanagan View
21-0012 RCS RMS Inc. Donna Adams View
20-0081 Stablex US ecology Pierre-Olivier Gagné View
19-0074 Chammas Cutters Inc. Michel Chammas View
19-0072 C. Steinweg, Inc. John Moors View
18-0147 Evonik Corporation Robert Miller View
18-0139 SorbTech, Inc. Joanna Kilburn View
17-0046 TT Club Mr. Michael Yarwood View
08-0118 Seaboard Marine Ltd. Mr. John Plasencia View
11-0197 Air Products & Chemicals, Inc. Mr. Joe DiGirolamo View
11-0297 Linde Gas North America, LLC Mr. Guy Dalton    View
15-0180 COSMO International Corporation Patricia M. Sobel View
11-0314 BioStorage Technologies Ms. Darcy Britt View
10-0183 Air Liquide America Specialty Gases LLC Mr. Ralph Diaz View
12-0118 RemTec International Ms. Patricia Burns View
10-0187 Schlumberger Technology Corporation Mr. Paul Lezak View
08-0197 Silver/Cims LLC Mr. Jim Silver View
15-0166 ICC Compliance Center Ms. Sändra Miller View
15-0059 Cargolux Airlines International SA Mr. Gerard Guillaume View
17-0005 Entegris Mr. Quentin Yarbrough View
17-0044 Laidlaw Carriers Tank LP Mr. Jim O'Hara View
09-0228 Trinity Manufacturing, Inc. Ms. Karen Messana View
08-0059 The Fertilizer Institute Ms. Pam Guffain View
14-0210 Brian Kurtz Trucking Ltd. Mr. David Skater View
10-0159 Sandia National Laboratories Robert Rivera and Monica Ruiz View
16-0141 AREVA, Inc. Mr. Glenn Mathues View
13-0214 3M Mr. Todd Strobe View
11-0297R Linde Gas North America, LLC Mr. Guy Dalton View
09-0212 Horizon Hobby, Inc. Mr. Travis Morenz View
09-0035 Rohm and Haas Chemicals Mr. Vitaly Volfson View
13-0033 Dangerous Good of America    Mr. Fred A Romero View
08-0303 OSI Ms. Carolynn Buenger                                      View
10-0065 TSO3, Inc. Mr. Jean-Martin Vallières View
16-0005 CMA CGM (America), LLC. Mr. Chris Godfrey View
14-0013 Adrian Shipman View
10-0043 Gefahrgutberatung/Gefahrgutausbilding Mr. Jens-Thomas Rueckert View
14-0139 Linde Gas North Mr. Guy Dalton View