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Section §173.403: Definitions

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 173.403 on the ECFR website

Interpretation Responses

Ref ID Date Company Name Individual Name Response Document
22-0014 I.C.E. Service Group & SPS Strategic Packaging Systems Mr. Kurt Colborn View
20-0046 R.B. Natali Consulting, Inc. Ronald B. Natali View
19-0070 VEGA Americas, Inc. Brett Kemphues View
18-0128 Atlantic Ro-Ro Carriers, Inc. Andrei Lazourenko View
18-0088 Settoon Towing Nicholas Kohnke View
18-0027 Veolia North America Ms. Jennifer Eberle View
18-0014 Nuclear Energy Institute Janet Schlueter View
18-0033 Occupational Services Inc. Linda Bray View
18-0004 Commercial Vehicle Safety Alliance View
18-0030 Lighting Technologies International, LLC Joe Rodriguez View
17-0047 Rob Scott View
17-0114 PHI.Inc Mr. Terry Myer View
05-0241 Envirocare of Utah, LLC Mr. Mark Ledoux View
16-0016 U.S. Customs and Border Protection Mr. Jason Hart View
01-0107 Radian International Mr. Andrew Romach View
05-0094 MHF Logistical Solutions Mr. Kurt Colborn View
15-0036 U.S. Department of Energy Mr. Dennis Claussen View
03-0061 MHF Logistical Solutions Mr. Kenneth M. Grumski View
00-0329 Regulatory Resources, Inc. Mr. Wade A. Winters View
15-0014 U.S. Department of Energy Mr. Dennis Claussen View
03-0071 SAIC Health Physicist Ms. Linda G. Bray View
11-0038 Los Alamos National Laboratory Mr. Donald Thorp View
06-0274 HMTC Training & Consulting Mr. Philip C. Rieke View
15-0056 Regulatory Resources, Inc. Mr. W.A. Winters View
06-0084 RWE NUKEM Corporation Mr. Stan Hodges View
02-0173 BAE Systems Michael S.Krupka View
98-0574 ADea Services, Inc. Mr. Leonard J. Warbiany View
13-0080 Detector Electronics Corporation Mr. Lee R. Zwiefelhofer View
04-0266 R.E. Ginna Nuclear Power Plan Mr. Mark Harrison View
16-0109 Spectrum Techniques Mr. Daniel Sims View
06-0002 MHF Logistical Solutions Mr. Kurt Colborn View
06-0002 MHF Logistical Solutions Mr. Kurt Colborn View
09-0206 State of Utah Department of Environmental Quality Mr. Dane Finerfrock View
06-0204 Mr. Jim Pitts View
04-0072 MHF Logistical Solutions, Inc Mr. C.S. Fossee View
16-0112 Atlantic Ro-Ro Carriers, Inc. Mr. Andrei Lazourenko View
06-0238 EnergySolutions Mr. James H. Portsmouth  View
07-0005 Monticello Nuclear Generating Plant Timothy M. Gallagher View
15-0195 Prairie Island Nuclear Generating Plant Mr. Clay Sweet View
10-0082 Osram Sylvania Mr. John Fichera View