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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
08-0271 Minnesota Pollution Control Agency Ms. Teresa Gilbertson View
08-0140 Burdette & Associates, Inc. Michael Burdette, P.E. View
PI-09-0006 State of Colorado Public Utilities Commission Mr. Stephan Pott, PE View
PI-08-0010 State of Colorado Public Utilities Commission Mr. Stephan Pott, PE View
08-0289 Durham, Jones & Pinegar, P.C. Mr. Michael F. Leavitt View
08-0223 High Q LLC Mr. Scott Bischoff View
09-0029 Northland President, Inc. Mr. Richard Maxwell View
08-0207 Cognis Oleochemicals LLC Mr. Sam Ghantous View
09-0024 Lia BD Consulting Barry Lia, Ph.D. View
09-0021 DENSO Manufacturing Tennessee, Inc. Mr. Bob Booker View
08-0215 Flash DOT Compliance Services Mr. Jaime Herrera View
08-0291 Evonik Degussa Corporation Mr. John Foglio View
08-0187 Crown Holdings, Inc. Ms. Maria L. Evangelista View
09-0002 RFD Beaufort Ltd. FAO Tommy Scott View
08-0137 National Motor Freight Traffic Association, Inc. Ms. Lisa K. Winter View
08-0286 Packaging Applications for Dangerous Goods, LLC Mr. David Gluntz View
08-0148 Energy Solutions Mr. James H. Portsmouth View
08-0310 SFB Plastic, Inc. Mr. John Fosse View
08-0217 Advance Engineered Products Ltd. Mr. Rick Campbell View
09-0003 Environet LLC. Ms. Tammy L. Blakeslee View
08-0152 North American Services Group Mr. Bill Youngs View
08-0293 S.H. Bell Company Mr. Chris McKenzie View
08-0280 Cerasis Inc. Mr. Frank Adams View
08-0024 Environmental Quality Management, Inc. Stone Point Landing Mr. Joseph D. Biss View
08-0121 Special Waste Disposal, Inc. Mr. John Grindal View
09-0006 SJ Transportation Co., Inc. Mr. Christopher P. Prioli View
09-0008 Mr. Patrick Oppenheimer FedEx Express View
08-0239 Thermo Fisher Scientific Customer Channels Group Mr. Gene Sanders View
08-0164 Labconco Corporation Mr. Daniel Taylor View
08-0303 OSI Ms. Carolynn Buenger                                      View
08-0305 Elpro Services, Inc. Mr. Martin Peter View
08-0174 YRCW- North American Transportation Mr. Robert A. Maberry III Sr. View
08-0244 University of the Sciences in Philadelphia Ms. Renee Siegel View
08-0248 American Trucking Associations Mr. Richard Moskowitz View
08-0296 Kott Koatings, Inc. Mr. John M. Kott View
08-0021 Energy Solutions Mr. James H. Portsmouth View
08-0282 Lantheus Medical Imaging Mr. Kevin Anderson View
08-0272 DuPont Company Mr. Randolph Martin View
08-0287 Remington Arms Company, Inc. Mr. Gregory D. Kehril View
08-0266 International Biophysics Corporation (IBC) Mr. William R. Wilkinson View
08-0268 University of Chicago Ms. Susan Grover View
08-0277 Mr. Lawrence W. Bierlein View
08-0258 Republic Airways Holdings Mr. John E. Martiney View
08-0190 Cytec Industries, Inc. Mr. James Sompii View
08-0294 The Law Offices of Michael A. Capuzzi Mr. Michael A. Capuzzi, Esq. View
08-0097 C&R Fleet Services, Inc. Mr. Anthony Reid View
08-0151 Van Hool NV Mr. Chris Vleugels View
08-0185 EHS Associates, Inc. Mr. Daniel J. Young View
08-0275 Atlantic RO-RO Carriers, Inc. Mr. Andrei Lazourenko View
08-0284 Momentive Performance Materials Mr. Michael T. Shamulka  View