USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

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
98-0275 Miller Products Company, Inc. Ms. Pat Czeczuga View
98-0283 Cotkin & Collins Mr. Cooper Collins View
98-0116 Fort Vale Mr. Don Kilgore View
98-0251 National Tank Truck Carriers, Inc Mr. Clifford J. Harvison View
98-0227 Manufacturers' Institute, Inc Mr. Robert Van Duzer View
98-0184 American Association for Respitory Care Ms. Kathleen Adams View
98-0230 BOC Gases Mr. John N. Thompson View
98-0604 National Propane Gas Association Mr. W.H. Butterbaugh, CAE View
98-0250 Safety Kleen Mr. Jerry Davis View
98-0232 Minntech Corporation Mr. Richard M. Ormsbee View
98-0130 Allied Universal Corp. Ms. Robin J. Eddy View
98-0263 JEVIC Transportation Inc. Mr. Samuel V. Yardumian View
98-0291 Scripto Tokai Mr. Lavern Johnson View
98-0209 Elf Atochem North America, Inc Mr. William Oister View
98-0277 Toyota Motor Sales, U.S.A.,Inc. Anthony P. Willson View
98-0605 U. S. Coast Guard J.B. Roberts View
98-0131 Saf-T-Pak, Inc. Mr. Eric Cook View
98-0273 Arctic Foundations, Inc. Mr. Edward Yarmak, Jr., P.E. View
98-0200 SRC Engineers, Inc. Mr. Stephen R. Callegari, Sr. View
98-0267 VFP Inc. Mr. David Brammer View
98-0242 Chautauqua Metal Finishing Supply Ms. Patricia A. West View
PI-98-0103 All American Pipeline Company Mr. Jordan R. Janak View
98-0120 Amerigas Partners, L.P. Ms. Jean S. Konowalczyk View
98-0261 Degussa Corporation Mr. John Foglio View
98-0233 HMT Associates, L.L.C. Mr. Gordon Rousseau View
98-0217 Polar Service Centers Mr. Mark Hughes View
98-0606 HMT Associates, L.L.C. Gordon Rousseau View
98-0214 Grace Tarr Corporation View
98-0252 H. A. Holden, Inc. Mr. Philip M. Hayden View
98-0235 Toyota Motor Sales, U.S.A., Inc. Mr. Anthony P. Wilson View
98-0223 Sea-Land Services Mr. Prabhu Natarajan View
98-0258 Cook Children's Medical Center Mr. Ray Crain View
98-0237 Director Spectra Gases, Inc. Ms. Elaine Bradford View
98-0213 International Fibre Drum Institute Mr. Gordon Rousseau View
98-0041 T.P.H. Management Service Ltd Mr. Donald H. Hausmann View
98-0221 Dangerous Goods and Cargo Security Program William Wilkening View
98-0125 Waste Management Federal Services Mr. J.G. Field View
98-0224 H.B. Fuller Automotive Company Mr. Eugene J. Secor View
CHI-98-003 Westchester County Thomas G. Gardiner, Esq. View
98-0201 Spectra Gases, Inc. Ms. Elaine Bradford View
98-0220 New York University Mr. Elliot Greenberg View
98-0150 Browning Chemical Corp. Mr. Bruce M. Pershan View
98-0169 Mind2Market Inc. Mr. Ray Williams View
98-0202 Southeastern Fumigants, Inc. Mr. Larry W. Massey View
98-0210 Wright Corporation Mr. Rick Wells View
98-0168 Yellow Freight System, Inc. Mr. Robert A. Maberry View
PI-98-0102 West Virginia Public Service Commission Mr. David A. Hippchen View
98-0207 MMA Mr. William J. Schuchman View
98-0159 Atotech USA Inc Mr. Scott Waddell View
98-0137 Safety Manager Stericycle Mr. Paul B. Hartman View