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
06-0161 Nazdar Limited Ms. Linda M. Bartram View
06-0079 House of Batteries Mr. Brion Munsey  View
06-0146 State of New Jersey Department of Environmental Protection Ms. Robert Gomez View
06-0149 Compliant Technologies, Inc. Mr. David Ellis View
06-0167 Cooper Power Systems, Inc. Mr. Darren Shequen View
06-0170 Airgas-SAFECOR Mr. John Anderson View
06-0162 Missouri Gas Energy Ms. Crystal Callaway View
06-0074 Hyundai America Shipping Agency Mr. Herb Giles View
06-0152 Hunton & Williams LLP Mr. Brooks M. Smith  View
06-0154 Transportation Systems Solutions Mr. Peter Olsen View
06-0158 Troxler Electronic Laboratories, Inc. Mr. Steve Browne View
05-0264 JFK International Airport Mr. James LoBello View
06-0127 Lockheed Martin Aeronautics Company Mr. Michael S. Fiddes View
06-0111 AmeriPath Ms. Julie Frail View
06-0145 Virginia Polytechnic Institute and State University Mr. Frank Imperatore View
06-0034 National Tank Truck Carriers, Inc. Mr. Thomas P. Lynch View
06-0156 FedEx Express Mr. Thomas J. Leech, III View
06-0094 Quest Diagnostics Mr. Nicholas Pagerly  View
06-0122 Minnesota Department of Transportation Mr. Michael Ritchie View
06-0143 Georgia Department of Public Safety Captain Bruce Bugg  View
06-0147 Mr. Patrick F. Reilly  View
06-0076 Regulatory Resources, Inc. Mr. Wade Winters  View
06-0113 RBC Dam Rauscher Mr.. Jay Jensen  View
06-0140 Minnesota Department of Transportation Mr. Kevin Kampa View
06-0139 Solutions, Inc. Mr. Victor Anderson  View
06-0138 Sharp Energy Mr. Larry R. Miller View
06-0040 Marquis Spas Mr. Gary Kertz View
05-0193 MGA Research Corporation Mr. Anthony J. Angello View
06-0035 Supervac 2000, Inc. Ms. Nathalie Doyon View
06-0135 Los Alamos National Laboratory Packaging and Transportation Mr. Joseph Lowery  View
06-0136 Samax Enterprises Mr. Perry J. Patton View
06-0114 Musket Corporation Mr. Doug Lumry  View
06-0097 Ms. Kristen Taddonio  View
06-0142 Associated Spring Raymond Mr. Thomas J. Fischer View
05-0075 SJC Compliance Education, Inc. Mr. Stephen Cansler View
06-0027 Mr. Steve Kranyec View
06-0071 Rieke Packaging Systems Mr. Gary Baughman View
06-0128 Mr. Richard B. Loden View
06-0105 Volvo Aero Services (Seattle) LLC Mr. Ronnie Hamblin View
05-0283 Transportation Development Group Mr. Jim Powell View
06-0002 MHF Logistical Solutions Mr. Kurt Colborn View
06-0002 MHF Logistical Solutions Mr. Kurt Colborn View
06-0082 3AL Testing Corporation Mr. Robert Fick View
06-0133 Global Fire and Safety, Inc. Mr. Bill McDonald  View
06-0072 HB Fuller Company Mr. Eugene J. Secor View
06-0103 Law Offices of Michael J. Pangia, P.C. Mr. Michael J. Pangia View
06-0134 Special Materials Company Mr. Adam Feldman View
04-0097 U. S. Army Corps of Engineers Marcia C. Davies, Ph.D. View
06-0003 Thompson & Simmons, PLLC Mr. Charles T. Simmons View
06-0132 Motor Carrier Compliance & Safety Co Mr. Jay Muratore View