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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
98-0424 American Trucking Association Mr. Paul M. Bomgardner View
98-0537 All-Pak, Inc. Mr. R. C. Watt View
98-0422 BMD Enterprises, Inc. Ms. Marilynn Dunn View
98-0423 Mr. Patrick G. Kruger View
98-0500 H.B. Fuller Automotive Company Mr. Gene Secor View
98-0525 Elkem Metals Company Ms. Sharon L. Thompson View
98-0407 Big T Transfer Inc. Ms. Lisa Smith View
98-0532 Delphi Energy & Engine Management Systems Mr. David McCullough View
98-0415 ROMIC Environmental Technologies Corp. Mr. Kurt Swart View
98-0405 ASi International Mr. Greg Lemley View
98-0539 Hercules Incorporated Mr. L. L. Kerstetter View
98-0529 Pall Corporation Ms. Susan Morrissey View
98-0401 Shipmate, Inc. Mr. Steven Charles Hunt View
98-0524 Hunt Shipmate, Inc. Mr. Steven Charles View
98-0558 Manchester Tank & Equipment Company Mr. Randy Wahl View
98-0584 Amerex Corporation Mr. Fred B. Goodnight View
98-0555 The Columbiana Boiler Company Mr. Aris Antoniou View
98-0503 United Surveyors of Chemicals, Inc. Mr. Jeffrey M. Moses View
98-0511 Environmental, Health & Safety Mr. Joseph W. Gentile View
98-0412 Technical Chemical Company Mr. Ruben E. Morales View
98-0518 Wastewater, Soil & Gas Analysis Inc. Dr. Kuldeep Verma View
98-0590 West Central Environmental Corp. Mr. Dana Murphy View
98-0413 Sierra Chemical, Co. Mr. Ron Shan View
98-0585 Stone Container Corporation Mr. Richard M. Thomas View
98-0510 HMT Associates, L.L.C. Mr. Gordon Rousseau View
98-0416 Degussa Corporation Mr. John Foglio View
98-0373 Signode Packaging Systems Mr. Mark T. Hughes View
98-0527 Stresau Laboratory, Inc Mr. Vince Mendoza View
98-0540 HMT Associates, L.L.C Mr. E.A. Altemos View
98-0400 Tamaya Chemical Corporation Mr. Steven Charles Hun View
98-0396 Currie Associates, Inc. Mr. John V. Currie View
98-0550 Laidlaw Environmental Services, Inc. Mr. Jerry D. Davis View
98-0578 Delta Liquid Energy Mr. Robert Jacobs View
98-0589 Ten-E Packaging Services, Inc. Mr. Robert J. Ten Eyck View
98-0542 Myers Industries Ms. Barb Germano View
98-0546 International Compliance Center Mr. Dwight Baker View
98-0399 Chemtech Products, Inc. Mr. Jim Winkler View
98-0410 United Parcel Services Mr. Samuel S. Elkind View
98-0549 Ross Trucking Co., Inc. Ms. Nancy McKnight View
98-0557 American Trucking Associations Mr. Paul M. Bomgardner View
98-0506 Minnesota Department of Transportation Mr. Michael Ritchie View
98-0521 Eurotainer USA, Inc. Mr. Terrence Noonan View
98-0541 Johnson Law Office, PC Ms. Joanna L. Johnson View
98-0547 Partners in Compliance, Inc. Mr. Jay Johnson View
98-0572 Raloid Corp. Mr. Robert A. Robbins, QAR View
98-0513 The Dow Chemical Company Mr. Hugh Taylor View
98-0545 Mr. Robert C. Franz View
98-0508 The Dow Chemical Company Mr. Hugh Taylor View
98-0538 Bell Atlantic Network Services, Inc. Ms. Patricia A. W. Murphy View
98-0564 Manchester Tank Mr. Randy Wahl View