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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
99-0115 Ocenco, Inc. Mr. Martin J. Tremblay View
99-0190 North Central Laboratories Ms. Pat Albrecht View
99-0201 FPPF Chemical Co., Inc. Ms. Michele A. Giusiana View
99-0160 Applied Specialties Inc. Ms. Adrienne B. Scheurman View
99-0173 Shao Chen Mr. Mike He View
99-0180 EdgeCo Mr. Nels Samuelson View
98-0371 Levine-Fricke Mr. Thomas J. Dolce, P.E View
98-0350 TEN E Packaging Mr. Robert J. Ten Eyck View
99-0107 National Distribution Warehouse Mr. Marlyn Boyce View
99-0158 Premedica Corporation Mr. Joseph K. Arsenault View
99-0064 Avonite, Inc. Mr. Gilbert G. Espinoza View
99-0111 Conley Corporation Mr. Aaron Moran View
99-0127 Federal-Mogul Power train Systems Mr. Scott Holder View
99-0101 Kuwait Airways Corp. Mr. Sooran Al-Qabbani View
99-0114 Poly Fiber, Inc. Mr. Gregory Albarian View
99-0151 Saltzman Consulting Services, Inc Ms. Susan C. Saltzman View
99-0142 DGI Training Center Mr. Sean Kelly View
99-0168 HMT Associates, L.L.C. Mr. Andy Altemos View
99-0155 Perkins Propane Gas, Inc Mr. John R. Perkins View
99-0016 Brent Industries Inc. Mr. Michael Culliton View
99-0001 Sharp Microelectronics Technology, Inc. Ms. Lesa L. Grant View
99-0163 Metropolitan Environmental, Inc. Mr. Thomas W. Moline View
98-0286 Polar Service Centers Mr. Mark Hughes View
99-0118 ABX Air, Incorporated Mr. Benjamin W. Taylor View
99-0046 Mr. Mark R. Maki View
99-0089 Delta Air Lines Inc. Mr. Inman Beavers View
99-0120 Chemtronics Mr. Bill Dowse View
98-0228 American Power Conversion Mr. Neil Rasmussen View
99-0145 PWN Environmental Mr. Bradford A. Gagnon View
99-0079 Lewis Marine Supply Mr. Keith L. Mauer View
99-0105 Chem Lab Products, Inc. Mr. Dana Wm. Somesla View
99-0119 Department of the Army Mr. Vernon E. Vondera View
99-0083 Polar Air Cargo Mr. Paul J. Zinza View
99-0078 Willett Labeling Company Ms. Alberta Millar View
99-0098 Dangerous Goods of America, Inc. Mr. Valois Pagan View
99-0093 Clariant Corporation Mr. Robert F. Rau View
99-0141 Austin Powder Company Mr. Larry J.(Scooter) King View
98-0374 Mitsubishi Motor Manufacturing of America Edwin C. Amsler View
98-0239 Ms. Donna J. Buckinger View
99-0067 Arnold & Porter Mr. Lawrence E. Culleen View
99-0071 Radian International Mr. Andrew N. Romach View
98-0601 Safety & Compliance Associates, Inc. Mr. Mike Lopez View
99-0073 Department of the Air Force SMSGT Timothy W. Stern, USAF View
99-0128 Safety and Compliance & Associates, Inc. Mr. Mike Lopez View
99-0112 Ludvik Development Company Mr. Oscar Mirabel View
99-0095 Mr. Mark Kloppel View
99-0097 Mr. Mark Villarino View
99-0126 Becton Dickinson Healthcare Systems Mr. Mark Welch View
99-0036 Marcus & Shapira LLP Ms. Elly Heller-Toig View
99-0088 Ms. Carolyn Kossik View