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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
23-0081 North American Transportation Consultants, INC. J.P. Gibbons View
24-0016 Owen 1683, LLC Craig Owen View
23-0062 W. R. Grace & Co. Paul Errichetti View
23-0106 ATECH Engineering Edward Mansell View
23-0078 Public Utilities Commission of Ohio Tom Forbes View
24-0019 ProteQ Mr. Marc Gordnier View
24-0018 Mr. Fred Storer View
23-0066 W.R. Grace & Co - Conn. Mr. Paul Errichetti View
22-0038 Daniels Training Services, Inc. Daniel Stoehr View
PI-24-0001 Colorado Energy & Carbon Management Commission Mr. Curtis Haverkamp View
PI-23-0006 Kinder Morgan Operation Support Group Mr. Jaime Hernandez View
23-0052 Dayton Freight Lines, Inc. Justin Sharkey View
23-0097 Hunting Titan, Inc. Joseph Murphy View
24-0010 AMETEK AMERON Patrick Schoenhoff View
23-0022 KC Partners Group Mr. Joseph E. Connelly View
24-0012 Kwik Trip Mr. Carl Suhr View
23-0041 United Testing Services Anthony Roston View
24-0006 Veolia North America Jennifer Fletcher View
24-0011 Ohio Public Commission Tom Forbes View
23-0067 Andelyn Biosciences Dave Curl View
23-0086 Azelis Ms. Cindy Murphy View
24-0020 Public Utilities Commission of Ohio Mr. Tom Bartfai View
PI-23-0011 Paradox Pipeline Mr. Todd Westcott View
PI-23-0013 Windler Ventures, LLC Mr. Cary Windler View
23-0093 Transportation Development Group Jim Powell View
23-0098 Consolidated Container Company William Dworsky View
24-0001 Ohio Public Utilities Commission Tom Forbes View
24-0017 Champion X Melanie Barker View
23-0035 Superior Plus Propane Mr. Tim Decker View
23-0055 Amazon Inc. Mr. Josh Galvarino View
23-0105 SET Environmental, Inc. David Olsen, Jr. View
23-0065 W. R. Grace & Co. Mr. Paul Errichetti View
23-0101 NRS Ocean Logistics Ltd. Ms. Nicole Enright View
23-0076 Mr. Tristan Amberger View
23-0042 Galiso, Inc. Mr. Jon Davignon View
23-0075 Roy Kluthe View
24-0024 Parker Hannifin Lord Corporation Erik Steinbeck View
23-0102 American Industrial Transport, Inc. Roger Dalske View
22-0087 Olin Corporation Daniel T. Stein View
PI-23-0018 State of Washington Utilities and Transportation Commission Regulatory Mr. Scott Rukke View
23-0096 Airborne Labs International, Inc. Aniyah Volpe View
23-0103 Logistics Specialist IV Shelly Stampfler View
24-0002 International Isotopes Inc. John J. Miller View
24-0007 ABC Nitrogen Service Corp Aimee Fontenot View
23-0009 DOT Training Solutions Rex Railsback View
23-0092 Encore Container Chas Key View
23-0072 Arma Container Corp. Mr. Howard Silverman View
23-0085 Texas Highway Patrol Dustin Henderson View
22-0107 Roadrunner Transportation System LLC Mr. Karl Kronau View
23-0027 Electronic Fluorocarbons Mr. Jason Bombard, PE View