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Section §173.56: New explosives-definition and procedures for classification and approval

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.

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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 173.56 on the ECFR website

Interpretation Responses

Ref ID Date Company Name Individual Name Response Document
23-0074 Raytheon Steven W. Steuer View
23-0019 AET Environmental, Inc. Frank Virginia View
21-0062 Institute of Makers of Explosives Susan JP Flanagan View
21-0095 DynaEnergetics US Inc. Mr. Ed Zinsmeyer View
21-0082 Onepoint4 Ltd. Peter Shelley View
21-0041 Mr. Robert J. Howell View
21-0009 BCA Packaging Services Nelson Kays View
21-0034 Keith Baecht View
20-0030 ORBITAL ATK Robert Weston View
20-0015 Onepoint4 Ltd. P. Shelley BEng (Hons), MISEE, MIExpE View
20-0012 Consolidated Nuclear Security, LLC Chris Carthel View
19-0108 Explosives Test Center, LLC Graham Walsh View
09-0013R Clean Harbors Environmental Services, Inc. Anthony Cellucci View
18-0141 Onepoint4 Ltd. P. Shelly BEng (Hons) View
18-0123 Jet Research Center Mark Cipolla View
18-0092 Grand Finale Entertainment, Inc. James Fish View
18-0124 Scopelitis, Garvin, Light, Hanson & Feary, PC Timothy W. Wiseman View
18-0012 United Kingdom Ministry of Defence Richard Hope View
07-0044 western Kentucky University Mr. Christopher J. Widman View
98-0331 Remington Arms Company, Inc. Mr. R. A. VanDuzer View
15-0110 Mace Tactical Solution, LLC Mr. Garnett Meador View
10-0110 Canadian Defense Liaison Staff Col. D.T. Erickson View
02-0198 Applied Biosystems David W. Olson View
11-0276 Mr. Lawrence W. Bierlein View
14-0047 Sandler, Travis & Rosenberg, P.A. Mr. Mark Ludwikowski, Esq. View
08-0179 DeOrchis & Partners, LLP Mr. Richard L. Furman View
13-0215 Savethesituation Ms. Eva Glimsche View
08-0185 EHS Associates, Inc. Mr. Daniel J. Young View
10-0171 AWE Mr. David A. Cocks View
12-0198 Pacific Scientific Energetic Materials Company Mr. Timothy S. Dillon View
10-0222 Environmental Resource Center Ms. Rebecca Spaulding View
16-0057 American Pyrotechnics Association Ms. Julie Heckman View
14-0201 ESCI EnviroServices, Inc Mr. Steven M. Lichten View
00-0136 HITECH Ms. Jackie Brian View
10-0177 CSE Corporation Mr. Jeff Tocci View
10-0253 AVOX Systems Inc. Mr. Joesph Contino View
02-0218 Alliant Techsystems, Twin Cities Arsenal Christopher J. Widman View
06-0157 Regulatory Resources Mr. Wade Winters View
16-0024 Williams International Mr. Stan Harrison View
CHI-10-003 B.J. Alan Company William A. Weimer, Esq. View
04-0121 General Dynamics - OTS Mr. John Wells View
09-0061 Thompson Hine LLP Mr. David M. Schwartz View
04-0113 General Dynamics - OTS Mr. John Wells View
04-0273 RUAG Ammorech GmbH Dr. Bernd E. Niekisch View
14-0098 Complete Compliance Services Mr. Len Satkowski View
05-0230 U.S. Department of Labor Mr. Michael P. Valoski View
06-0194 North American Automotive Hazmat Action Committee Mr. Dave Madsen View
14-0237 Textron Systems, Weapons & Sensor Systems Mr. James Baustert View
14-0248 R&S Compliance group, LLC. Mr. David Rivers View
14-0182 Reagent Chemical Mr. Robert Dritschel View
10-0087 US Dynamics Corporation Mr. George Jantzen View
09-0013 Clean Harbors Environmental Services, Inc. Mr. Anthony P. Cellucci View
09-0015 MDM Ltd. & Black Mag Industries Mr. Craig M. Sanborn View
08-0300 DeOrchis & Partners, LLP Mr. Richard L. Furman View
16-0023 Williams International Mr. Stan Harrison View
09-0022 NASA Wallops Flight Facility Mr. Ernest Cornwell View
14-0006 Veolia ES Technical Solutions, L.L.C. Mrs. Jennifer Eberle View
01-0262 BAE Systems, Ordnance Systems, Inc. Mr. Charles Richmond View