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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
05-0200 Mr. Ed Mansell View
06-0044 Gallagher & Howarth, P.C. Ms. Liese G. Howarth View
06-0053 Pfizer, Inc. Ms. Debbie Hape View
06-0054 Scranton Cooperage, Inc. Mr. Eric Spatt View
06-0065 Neupauer Industries Inc. Mr. Harold Zimmerman View
06-0049 Vinson & Elkins Thomas H. Wilson View
05-0191 Industrial Health and Safety Consultants, Inc. Denese A. Deeds, CIH View
05-0120 Cayias Consulting Mr. John Cayias View
06-0050 REG Scan Mr. Russ Shanahan View
04-0119 Monsanto Company Mr. William J. Briner View
06-0056 NACA Logistics Mr. Eric Fischer View
05-0196 Arkansas Department of Environmental Quality Mr. Robert Hunter View
05-0109 GATX Rail Mr. Doug Mullins View
06-0037 Waste Technology Services, Inc. Ted L. Nebrich, Jr., CHMM, QEP, REM View
06-0032 Mr. Thomas Richichi View
05-0290 Galls/Aramark Inc. Mr. Carl Jackson View
06-0021 Intertek Caleb Brett New Orleans Mr. Scott Fenwick View
06-0042 State of New Jersey Mr. Robert Gomez View
06-0039 Shane Havoc Consulting, LLC Dr. Gregory J. Sutherland  View
05-0218 City Carbonic Sales & Service Ms. Amy Morgan Bruecks View
06-0057 Akzo Nobel Chemicals Inc. Mr. Mark A Connolly View
06-0047 Tyco Specialty Products Ms. Nicole Curcio View
06-0019 3M Company Mr. Richard L. Sheehan View
06-0036 Greif Mr. Rich Kovaleski View
06-0012 Mr. Anthony J. Kesslak View
06-0025 University of New Hampshire Mr. Andy Glode View
06-0033 Mr. Christian W. Solum View
06-0017 Martinair, Inc Mr. Rob Riggott View
05-0313 Chevron U.S.A. Inc. Ms. Patricia E. Lin View
05-0259 Akzo Nobel Chemicals Mr. Mark A. Connolly View
05-0310 Airgas, Inc Mr. Randy Porter View
06-0008 North Carolina State Highway Patrol Captain George E. Gray, Jr View
04-0068 Inland Paperboard and Packaging, Inc Mr. John H. Rutherford View
06-0013 Pennsylvania Department of Environmental Protection Mr. Frederick P. Walter, Jr. View
06-0029 Fortco Plastics, Inc. Mr. Stephen Jetter View
06-0030 TEN-E Packaging Services, Inc. Mr. Robert J. Ten Eyck View
06-0011 Mr. Lawrence J. Maron View
06-0014 Frontier Technology Corporation Mr. Edward F. Janzow View
06-0005 Byfield Marine Supply Mr. Keith L. Mauer View
06-0024 Allied Universal Corporation Ms. Robin J. Eddy Bolte View
05-0210 Sandia National Laboratories Mr. Leighton Ford View
04-0182 Occupational Safety Specialists Mr. Steve Laughlin View
05-0315 Global Logistics Services Ms. Joan M. Boardman View
05-0047 Venture Lighting International, Inc. Mr. Clinton M. Giannett View
05-0299 Akzo Nobel Chemicals Mr. Mark A Connolly View
05-0287 Airgas, Inc. Mr. John Anderson View
05-0318 Director, Manufacturing Mr. Mike Conway View
05-0001 Mr. Donald Stiger View
05-0233 Indiana Propane Gas Association Mr. John Shimer View
05-0238 Consultant Mr. Charles E. Tudor View