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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
13-0140 Linden’s Propane Mr. Ray Anielski View
CHI-13-003 T-MAK Labs, Inc. Tim Phelan View
13-0132 Maine Department of Transportation Environmental Office Mr. Dwight Doughty, Jr. View
13-0110 Kidde-Fenwal, Inc. Mr. Richard Lupien View
13-0134 Battery USA Mr. Jim Lawless View
13-0004 Airgas SAFECOR Mr. John Anderson View
13-0126 Naval Surface Warfare Center Energy Power & Interconnect Technologies Division Mr. Mark Tisher View
CHI-13-001 Lawrence W. Bierlein View
12-0144 HazMat Resources, Inc. Mr. Danny Shelton View
13-0093 Triumvirates Environmental Mr. Patrick Hallinean View
13-0122R URS Corporation Mr. Andrew N. Romach View
13-0130 Weiman Products, LLC Mr. Matt Malec View
13-0127 Public Utilities Commission of Ohio Transportation Department Mr. Tom Forbes View
13-0142 EHS Assurance Mr. Andrew Peterson View
13-0077 Bellevue Hospital Center Mr. Kieran Toale View
13-0089 Plunkett Cooney Mr. Jerome A. Galante View
13-0091 Gh Package/Product Testing and Consulting, Inc. Mr. Ronald J. Sorrell View
13-0125 URS Corporation Mr. Andrew N. Romach View
13-0101 Regulatory Resources, Inc. Mr. W.A. Winters View
13-0106 Kriska Transportation Mr. Bob Duncan View
13-0111 Baker Hughes Mr. Aubrey R. Campbell View
13-0083 Shane Havoc Consulting, LLC Mr. Gregory Sutherland, Ph.D. View
13-0070 Safeway, Inc. Mr. David Tobin View
13-0117 DuPont Company Mr. Randy Martin View
13-0071 Authorized Testing, Inc. Mr. David Fountain View
13-0073 Aceto Corporation Ms. Suhey Francisco View
13-0108 Eastex Crude Company Ms. Kathy Harris View
13-0076 Patterson Companies, Inc. Mr. Robb Boros View
13-0109 Veolia ES Technical Solutions, L.L.C. Ms. Jennifer Eberle View
13-0072 DG Advisor, LLC Mr. Ben Barrett View
13-0058 The Council on Safe Transportation of Hazardous Articles, Inc. Ms. Lara Currie View
13-0121 ClearEdge Power Mr. Ron Collins View
13-0081 Kriska Transportation Mr. Rob Duncan View
13-0112 Great Lakes Custom Law Mr. Jason P. Wapieninick View
13-0085 UPS Mr. Samuel S. Elkind View
13-0135 Patterson Companies, Inc. c/o Patterson Logistics Services, Inc Mr. Robb Boros View
13-0092 Linde Gas North America LLC Mr. Guy Dalton View
13-0063 Mr. Andrew Walleck View
13-0065 Huntsman LLC Mr. Mike Stillwell View
13-0094 UPS Mr. Samuel Elkind View
13-0096 Manufacturing and Supply Chain Services Mr. Todd A. Strobel View
13-0102 DuPont Global Logistics Mr. Kevin M. Greene View
13-0113 Alden Leeds, Inc. Mr. Mark Viscont View
13-0080 Detector Electronics Corporation Mr. Lee R. Zwiefelhofer View
13-0087 Military Surface Deployment and Distribution Command Mr. Daniel A. Maham View
13-0097 BASF Corporation Mr. Joseph Matousek View
13-0068 New York State Department of Environmental Conservation Alan G. Woodard, Ph.D. View
13-0015R Joseph Hamill, P.E. U.S. Army ARDEC-Picatinny View
13-0107 A. Duie Pyle Inc. Mr. Rich Kaczynski, CDS View
13-0046 FedEx Freight, Inc. Ms. Sandra Richesin & Mr. Mike Brust View