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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).

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.

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
20-0031 Mark B. Hawk View
20-0034 Railsback Safety Professionals LLC Rex Railsback View
19-0100 Global Cellulose Fibers Paul Bissett View
20-0018 Mark B. Hawk View
20-0025 Entergy Donnie James View
19-0138 Gorick Construction Co., Inc. Alfred Gorick View
11-0020 Department of the Air Force Ms. Robbin L. Miller View
20-0022 Railsback HazMat Safety Professionals LLC Rex Railsback View
18-0153 FabTech Services, LP Jason Streber View
19-0088 TerraTrike Lisa Permesang View
19-0114 Entegris, Inc. Mr. James V. McManus View
20-0007 Oxyde Chemicals, Inc. Mr. Adrian Medina View
20-0012 Consolidated Nuclear Security, LLC Chris Carthel View
20-0032 Andres A. Burgos View
19-0137 Lithium-Batterie-Service GbR Eva Glimsche View
20-0016 SDS Refrigerant Service Brian Conners View
20-0020 Environmental Resource Center Ms. Kristie Absher View
19-0108 Explosives Test Center, LLC Graham Walsh View
20-0014 Reagent Chemical & Research Inc. Robert Dritschel View
19-0133 Dangerous Goods SME William Canterbury View
20-0004 North American Automotive Hazmat Action Committee Wayne Shafer View
PI-20-0007 IBEW Local 1245 Mr. Alexander Pacheco View
PI-20-0009 Public Advocates Office, California PUC Mr. Darwin E. Farrar View
19-0104 Public Utilities Commission of Ohio Tom Forbes View
PI-20-0005 Commonwealth LNG Mr. Scott Ray View
19-0076 TransQuip USA, Inc. Joe Becherer View
20-0003 Texas Department of Public Safety Corporal Casey Jones View
19-0129 Goal Zero Christie Babalis View
19-0105 United Initiators, Inc. Mr. Jeremy Pogorelec View
19-0123 AECOM Ms. Danielle Heaney View
20-0019 National Motor Freight Traffic Association, Inc. Lisa O'Donnell View
PI-20-0003 Counsel for Markwest Mr. Keith J. Coyle View
PI-20-0004 Buckeye Texas Processing, LLC Mr. Kevin Burke View
19-0128 Tyson Foods Carolyn Griffith View
19-0074 Chammas Cutters Inc. Michel Chammas View
19-0036 Hazmat Safety Consulting Bob Richard View
19-0125 Guthrie Heli-Arc, Inc. Kristen Powell View
PI-19-0014 Plastics Pipe Institute Dr. Randy Knapp View
19-0056 Woodard & Curran Kelly Camp View
19-0109 Worthington Cylinder Corporation Shane Decker View
19-0130 Matson Clifford Bartley View
19-0132 Robatel Technologies Mr. Jared Bower View
19-0124 Dru Chem Inc. Bill Krause View
PI-19-0002 Cal Farley's Boys Ranch Mr. Mark Al Strother View
19-0103 J Lazarus Consulting & Training, LLC Josh Lazarus View
19-0075 LORD Corporation, Saegertown Operations Erik W. Steinbeck View
19-0089 Uniweld Products, Inc. Janet Beets View
19-0107 Lowther Johnson Attorneys at Law, LLC Craig F. Lowther View
PI-19-0016 Pennsylvania Public Utility Commission Ms. Stephanie M. Wimer View
19-0111 Fuelie Systems, Inc. Thomas Stumpf View