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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
14-0174 Lufthansa Cargo Mr. Hilmar Leng View
14-0197 Philips Respironics Ms. Collen Witt View
14-0047 Sandler, Travis & Rosenberg, P.A. Mr. Mark Ludwikowski, Esq. View
14-0064 NitroxFox LLC Mr. John Fox View
14-0152 Space Information Laboratories Mr. Nick Pelster View
14-0142 Transportation Compliance Associates, Inc. Mr. Mike Alston View
14-0149 Mr. Armando Sancerni View
14-0189 Mitsubishi Motors North America Ms. Dawn Perry View
14-0162 Global Satellite Engineering Mr. Scott Walters View
14-0183 Denton Police Department Mr. William Burson View
14-0141 Innovage, LLC Mr. Ron Van Bavel View
PI-14-0013 Michigan Public Service Commission Mr. David J. Chislea View
14-0154 Pitt Ohio Mr. Timothy L. Stipcak View
14-0098 Complete Compliance Services Mr. Len Satkowski View
PI-14-0012 Williams West, Gas and Liquids Mr. Jared Ellsworth View
14-0153 Deitrich Engineering Mr. David Deitrich View
14-0058 Transportation Systems Solutions Mr. Peter Olsen View
14-0139 Linde Gas North Mr. Guy Dalton View
14-0128 University of Minnesota Mr. Michael Maurer View
14-0160 North America Dangerous Cargo (Maersk) Mr. Charles A. Giglia View
14-0173 Sika Corporation USA Mr. Arthur Van Houten View
14-0089 URS Corporation Mr. Andrew Romach View
14-0071 Willaims International Mr. Stan Harrison View
PI-14-0007 Duke Energy Florida Mr. Reginald Anderson View
PI-14-0006 Mr. Mark C. Wiggin Brooks Range Petroleum View
14-0018 URS Corporation Mr. Andy N. Romach View
14-0123 Guerrilla Air/ Tiberius Arms Mr. Gio Islas View
14-0133 Virginia State Trooper Mr. Kevin Teter View
14-0151 REI Mr. Terry Holland View
14-0156 URS Corporation Mr. Andrew Romach View
14-0137 Vonco Products, LLC. Mr. Keith E. Smith View
14-0138 Polytek Development Corp Mr. Keith E. Smith View
14-0136 5N Plus Wisconsin, Inc. Ms. Laura Buholca View
14-0069 Environmental Management, Inc. Mr. Jamie Newton View
13-0215 Savethesituation Ms. Eva Glimsche View
14-00132 Quest Diagnostics Mr. Nicholas Pagerly View
14-0094 Western Sales and Testing of Amarillo, Inc. Mr. Mark Griffin View
14-0124 HSB Global Standards, Inc. Mr. Oberst Mulet View
14-0104 Trident Safety Group Mr. Richard J. Walsh View
14-0155 Communication Center Mr. Ed Gruber View
CHI-14-002 Bullfrog Fire & Safety Kristie Rink View
14-0140 Centers for Disease Control and Prevention Dr. Paul Meechan View
14-0070 Quest Diagnostics Mr. Nicholas Pagerly View
14-0127 TASER International, Inc. Ms. Holly Gibeaut View
14-0145 U.S. Department of the Interior Kim A Thorsen View
14-0150 U.S. Department of Justice Mr. Ronald B. Turk View
14-0150 U.S. Department of Justice Mr. Ronald B. Turk View
14-0103 Von Briesen & Roper, S.C. Attorneys at Law Mr. Mark F. Foley View
14-0106 J.B, Hunt Transport, INC Mr. James Cherry View
14-0080 Discovery Laboratories, Inc Ms. Louise J. Calabretta View