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Letters of Interpretation

PHMSA has published several Frequently Asked Questions (FAQs) documents on programmatic topics. Please review these documents here at: https://www.phmsa.dot.gov/about-phmsa/phmsa-faqs.

Additionally, Office of Hazardous Materials Safety has published Hazardous Materials FAQs based on letters of interpretation on the following topics:

Office of Hazardous Materials Safety: For questions about transporting hazardous materials, needing clarifications of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180), or requesting a formal letter of interpretation, please go to the Hazardous Materials Information Center (HMIC) page for contact information (phone and email address). Pending interpretation letters that are under review by the Office of Hazardous Materials Safety can be found at Pending Hazardous Materials (Hazmat) Interpretations.  

Office of Pipeline Safety: 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: pipeline_interp_submittal@dot.gov. 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.

Interpretation letters under review are available at the Office of Pipeline Safety’s Interpretation Review page. To submit comments on an interpretation under review, proceed to the Interpretation Review page, locate the interpretation to comment on, and click the appropriate link to submit a comment on the corresponding interpretation. Comment submissions will be accepted for 30-days after the interpretation letter is posted.

This section of the website below provides the ability to find regulations information including regulations parts, content of sections, and interpretations for regulations sections. A list of parts, identified by the part number and subject is also provided. 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.

The eCFR is also searchable by keyword and other available options on the eCFR website. To search and browse regulations using the eCFR website, use the link below. For assistance, please send an email to PHMSA.Webmaster@dot.gov.

Search the eCFR

Interpretations Reference #

Search Tip: Use quotation marks to search for commonly used phrases, such as “gas transmission” or “cargo tank motor vehicle.”
E.g., 02/09/2021
E.g., 02/09/2021
Ref ID: Date Company Name Individual Name Response Document
07-0059 UPS Hydrostatic Shop Mr. Robert A. Stewart  View
06-0278 National Transportation Safety Board Ed B. Dobranetski, P.E. View
07-0014 Arizona Public Service! PVNGS Mr. Terrance Dickerson View
07-0015 EHS Associates, Inc. Mr. Byron Snapp View
07-0040 Public Works Department Jacksonville Ms. Kia Trace  View
07-0047 Fluoro-Seal International Mr. Paul J. Crook View
07-0058 Approved Fire Protection Company Robert Bailey View
06-0211 URS Corporation Mr. Andrew N. Romach View
07-0043 Western Kentucky University Mr. Gary M. Spichiger View
07-0021 Ariel Corporation Ms. Betty Hicks View
06-0239 Severn Trent Laboratories, Inc. Mr. William J. Geibel View
07-0052 Compliant Technologies, Inc. Mr. David Ellis View
07-0009 gh Package & Product Testing and Consulting, Inc. Mr. H. Perry Hock View
06-0198 DuPont Global Logistics Mr. Kevin M. Greene View
06-0263 Packaging Technology Center Mr. Thomas Schneider View
06-0284 Thompson Coburn LLP Mr. Anthony A. Anderson  View
07-0024 Veolia ES Technical Solutions, L.L.C. Ms. Jennifer Eberle View
07-0016 Mr. Dave Middleton View
07-0017 The Valspar Corporation Eric Barcaskey View
07-0019 Hy Yield Bromine Inc. Mr. Byver Daniell View
07-0057 Stericycle, Inc. Ms. Selin Hoboy  View
07-0046 Degussa Corporation Mr. John Foglio View
07-0035 Cornerstone Systems. Inc. Mr. Jonathan Ward View
07-0038 Lockheed Martin Missiles and Space Company Mr. Jim Hara  View
07-0025 LMC Pathology Services Ms. Jane Swerdlow View
07-0010 United States Coast Guard Mr. J.E. Pomajzl View
07-0018 Saf-T-Pak Gail Ryckis-Kite View
07-0005 Monticello Nuclear Generating Plant Timothy M. Gallagher View
07-0004 Volunteer Drum R. Jack Oody View
07-0023 NM Scientific Lab Ms. Pamela Morden MT (ASCP), MPH View
07-0007 Foley & Lardner, LLP Ms. Katherine E. Lazarski View
07-0020 Applied Biosystems Ms. Connie Roxas View
06-0269 Inmark, Inc. Mr. Junius "Jay" Johnson  View
07-0012 HMT Associates Mr. E. A. Altemos View
PI-07-0100 National Transportation Safety Board Mr. Rod Dyck View
PI-07-0101 National Transportation Safety Board Mr. Rod Dyck View
PI-07-0001 National Transportation Safety Board Mr. Rod Dyck View
07-0002 UPS Hydrostatic Shop Mr. Robert A. Stewart View
06-0191 The Pinehurst Office Center Mr. Gary A. Peters View
06-0157 Regulatory Resources Mr. Wade Winters View
06-0197 United States Coast Guard MST2 Danielle Galligan  View
07-0003 Commonwealth of Virginia Department of State Police Sgt. David P. Feather View
07-0006 Sasol North America, Inc. Ms. Sheryl Small View
PI-07-0105 CPN Pipeline Company Mr. Scott Vickers View
06-0203 Minnesota Department of Transportation Mr. Michael Ritchie View
06-0205 Kajuligan Corporation Mr. Cliff Croft  View
06-0207 Fisher Scientific International, Inc. Mr. Gene Sanders View
06-0257 Broco, Inc. Mr. Tom Joos  View
06-0213 Allied Universal Corporation Ms. Robin J. Eddy Bolte View
06-0268 Bonar Plastics, Inc. Mr. Craig Heinze View