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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
03-0130 New York State Department of Environmental Conservation Division of Solid and Hazardous Materials Mr. Paul R. Counterman, P.E. View
03-0151 Dominion Generation Mr. Doug Noce View
03-0002 Sunoco, Inc. Mr. Michael Alston View
02-0330 SMI Companies Michael W. Splane View
CHI-03-001 Department of California Highway Patrol Commissioner Helmick View
02-0305 Keller and Heckman LLP Michael F. Morrone View
03-0139 Brink's U.S. Mr. Stan Turbyfill View
03-0090 Lansmont Corporation Ms. Tramy Lieu View
03-0065 Eliokem, Inc. Mr. Dennis McMahan View
03-0011 Mr. John L. Hoffer View
03-0085 Core Foam Mr. Richard Porter View
02-0314 Aero Vironment Inc. Erica Jenkins View
03-0114 Dupont Global Services Business Mr. Randolph Martin View
03-0135 American Trucking Associations Mr. Richard Moskowitz View
03-0018 Arkansas Children's Hospital Mr. Wes Ware, BS, RRT, NREMT View
03-0030 Department of the Army Mr. Patrick M. Haas, P.E. View
03-0077 Waste Technology Services, Inc. Mr. T.L. Nebrich, Jr. View
03-0066 Patrick J. Kelly Drums, Inc. Mr. Harold Aranow View
03-0093 Riddick Engineering Corporation Mr. Chris J. Teas, PE  View
03-0096 Fisher Chemicals Ms. Jeanette DeGennaro View
PI-03-0102 City of Mesa Mr. Michael Comstock View
PI-03-0103 Enron Pipeline Services Company Mr. David L. Johnson View
PI-03-0104 Montana-Dakota Utilities Company Mr. Douglas M. Lee, P.E. View
PI-03-0105 Commonwealth of Pennsylvania Public Utility Commission Bureau of Transportation and Safety Mr. Paul Metro View
02-0212 Wal Mart Stores Sue Eaton View
02-0126 Allied Universal Corporation Robin J. Eddy Bolte View
03-0044 Mr. Scott C. Morrison View
03-0126 HQ US Army Joint Munitions Command 1 Mr. Kelly W. Crooks View
03-0112 Duratek Ms. Kathryn W. Pacha, CET, CIT View
03-0110 Laboratory Corporation of American Mr. Donald E. Horton, Jr. View
03-0103 South Florida Plastics, Inc. Mr. John S. Srokose View
03-0122 Century International Arms, Inc. Mr. Gary A. Beagle View
03-0124 Dart Container Corporation Ms. Amanda Bishop View
03-0057 Allied Universal Corp. Ms. Robin J. Eddy Bolte View
02-0191 University of Hawai'i at Manoa Tim O'Callaghan View
02-0244 Environmental Resource Center Pretlo V. Knight View
02-0222 Solutions, Inc. Victor B. Anderson View
03-0330 Dangerous Goods Advisory Council Mr. Alan I. Roberts View
03-0117 McCarthy, Sweeney & Harkaway, P.C. Lawrence W. Bierlein, Esq. View
03-0048 Environmental Rernediation Systems, Inc. Mr. Danny R. Hubbard II View
03-0028 Roadway Express Mrs. Lori Leonti View
02-0229 The Toro Company Mike O'Connor View
03-0115 McCarthy, Sweeney & Harkaway, P.C. Mr. Lawrence W. Bierlein, Esq. View
03-0049 Latham & Watkins LLP Mr. Kelly E. Richardson View
03-0088 Vought Aircraft Industries, Inc. Mr. David Norton View
03-0047 Halliburton Energy Services Mr. Johnny Cathey View
03-0078 Innovative Solutions & Technologies, L.L.C. Mr. Mike Lely View
04-0038 McCarthy, Sweeney & Harkaway, P.C. Lawrence W. Bierlein, Esq. View
02-0234 HB Fuller Company Gene Secor View
03-0072 New York State Department of Environmental Conservation
Division of Solid and Hazardous Materials 		Mr. Paul R. Counterman, P.E. View