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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
09-0063 Bard Brachytherapy, Inc. Mr. Edward A. Zdunek View
09-0055 MCSAP, Troop I, Olathe Mr. Rex Railsback View
PI-09-0005 Equistar Chemicals, LP Mr. Franklin Stagg View
PI-08-0003 Equistar Chemicals, LP Mr. Franklin Stagg View
09-0056 Mr. Gene Sanders Thermo Fisher Scientific View
09-0034 Challenge, Inc.                                                     Mr. Keith Hauser                                                         View
09-0036 Packaging Applications for Dangerous Goods, LLC Mr. David C. Gluntz View
09-0041 DCMA Phoenix Mr. Josh Shea View
09-0026 Titan Specialties LTD Ms. Shelley Espinoza View
09-0010 Pentair Water Group, Inc. Mr. John F. Di Leo View
09-0051 Hazard Solutions LLC Mr. Arthur Mahoney View
09-0042 Thermo Fisher Scientific, Customer Channels Group Mr. Gene Sanders View
09-0039 HazMat Resources, Inc. Mr. Danny Shelton View
09-0040 USCG TRACEN Yorktown (tmst) Mr. Kevin Henson View
09-0045 DuPont Sourcing & Logistics Mr. Thomas Reese View
09-0025 The Wicks Group, PLLC Mr. Lindsay W. McGuire View
08-0300 DeOrchis & Partners, LLP Mr. Richard L. Furman View
09-0007 Mr. Joseph A. Taranovich American Honda Motor Company View
08-0308 URS Corporation Ms. Erin N. Jarman View
08-0150 Mr. William J. Briner View
08-0153 HazMat Resources, Inc. Mr. Daniel G. Shelton View
08-0288 Kaplan Kirsch & Rockwell LLP Mr. Charles A. Spitulnik View
08-0306 White River Distributors Mr. David Fulbright View
08-0249 Stericycle, Inc. Mr. Dan Fadgen View
08-0171 Hoyt and Blewett PLLC Mr. Drew Blewett View
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