USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

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
15-0169 Amazing Products Inc. Ms. Jackie Skaggs View
15-0204 Crowley Liner Service Mr. Michael Lesser View
15-0178 Miller Transportation Services, Inc. Mr. Kenny Prather View
15-0222 COWAN Mr. J. David Shaeffer View
15-0118 National Association of Fire Equipment Distributors Mr. Norbert Makowka View
15-0131 Tyco Fire Protection Products Mr. Josh Lepinski View
15-0242 AmeriGas Propane Mr. Christopher Wagner View
14-0215 U.S. Environmental Protection Agency Ms. Nancy Fitz View
15-0242 AmeriGas Propane Mr. Christopher Wagner View
15-0099 Girard Equipment, Inc. Mr. Glen Harm View
15-0165 Air General Mr. Dennis Franco View
15-0166 ICC Compliance Center Ms. Sändra Miller View
15-0192 Mr. David Gobaud View
15-0146 MGA Research Corporation Mr. Michael Greiner View
15-0135 HWN Resources, LLC. Audrey Hallinger View
15-0168 AECOM Andrew N. Romach View
15-0201 Arkema Ms. Christina Kurtz View
15-0020 South Carolina Department of Health and Environmental Control Bureau of Laboratories Mr. Brian Gootee View
15-0102 Mallinckrodt Pharmaceuticals, formally Ikaria, Inc. Mr. Juan Miró View
15-0096 HazMat Resources, Inc. Mr. Danny Shelton View
15-0180 COSMO International Corporation Patricia M. Sobel View
15-0055 Mr. Attila Sonkoly View
15-0125 Westpak, Inc. Mr. Jorge Campos View
15-0027 Texas Instruments Incorporation Mr. Louis Le View
15-0157 Fleet Services Business Department Ms. Elizabeth Carson View
15-0148 New Jersey State Police Lt. John V. Guzzo View
15-0119 Information and Insights Mr. Kevin Skerrett View
15-0133 National Steel Car Limited Mr. Max Vanderby View
15-0151 HS&E Coordinator Mr. Peter Leus View
15-0100 Rayovac Corporation Mr. Richard Weinberger View
15-0043 Ingram Micro Inc. Mr. Glenn Williams View
15-0159 American Seafood's Group, LLC Mr. Ron Rogness View
15-0147 Argus Petroleum Transportation North America Mr. Mark Babineck View
15-0077 Lawrence Livermore National Laboratory Mr. Rod Coleman View
15-0130 Green Environmental Consulting Ms. Peggy Haase View
15-0113 Evonik Corporation Mr. Robert Miller View
15-0122 Hazmateam, Inc Mr. Paul Dambek View
PI-15-0004 Alaska LNG Mr. Rick Noecker View
PI-15-0003 Caelus Energy Alaska LLC Mr. J. Patrick Foleyr View
PI-15-0005 Bangor International Airport Mr. Anthony P. Caruso View
15-0062 Authorized Testing Inc, IA02 Mr. David Bacca View
15-0141 Daniels Training Service Mr. Daniel Stoehr View
15-0134 Alaska Airlines - SEADG Mr. Mike Tobin View
15-0120 Daniels Training Services Daniel Stoehr View
15-0111 Oxus America Mr. Ryan Lenaric View
15-0121 The Lane Construction Corporation Ms. Michele A. Jacobs View
14-0230 The Chlorine Institute Ms. Robyn Kinsley View
15-0047 Columbus Chemical Industries Ms. Laura Buholca View
15-0103 VEOLIA NORTH AMERICA Ms. Jennifer Eberle View
15-0094 Viking Packaging Mr. Les Adolph View