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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
16-0050 Hydro-Test Products, Inc. Mr. Tom Sauta View
15-0230 The Chlorine Institute Ms. Robyn Kinsley View
15-0144 Labelmaster Services Mr. Robert Richard View
16-0122 PRI International, Inc. Mr. Vincent Vitollo View
16-0026 Daniel Training Services Mr. Daniel Stoehr View
16-0014 COSTHA Ms. L'Gena Shaffer View
PI-16-0002 Bureau Veritas North America, Inc. Mr. Nate Chandler View
PI-15-0012 GE Oil and Gas Mr. Lee Strobel View
16-0037 US Zinc Mr. John Williams View
16-0047 National Aeronautics and Space Administration Mr. Russell Clautice View
16-0066 Dangerous Good of America Mr. Fred Romero View
16-0032 TEN-E Packaging Services, Inc. Mr. Robert TenEnyck View
16-0058 Nebraska State Patrol Mr. Brad Wagner View
16-0064 OR-CAL Inc. Ms. Brooke Baker View
16-0043 Cliff Bartley Consulting Mr. Cliff Bartley View
16-0030 Pioneer Tank Lines, Inc Mr. Larry Nielsen View
15-0235 Airgas-SAFECOR Mr. John Anderson View
15-0059 Cargolux Airlines International SA Mr. Gerard Guillaume View
16-0057 American Pyrotechnics Association Ms. Julie Heckman View
15-0174 Japan Aero Pressure Co., Ltd. Mr. Takashi Hashimoto View
16-0015 Consultant to Bosh Global Services Mr. Fred Marks View
16-0004 Texas Department of Public Safety Trooper Kelley F. McClatchy View
16-0018 UPS Airlines Mr. Bob McClelland View
16-0033 Mr. Daniel A. Justis View
15-0040 Wiley Rein LLP Mr. George Kerchner View
16-0034 Texas Machine Gun & Ordnance Mr. Sean Lindley View
15-0210 E.V. Logistics Coordinator Mr. Mike Casas View
15-0117 Intellectual Criminal Investigation Squad Investigator JI-hoon Chang View
15-0219 Intelligent Energy Mr. Douglas Knight View
16-0028 New York State Department of Health Mr. Corey Bennett View
15-0229 Idaho State Police Mr. Thomas Wright View
16-0005 CMA CGM (America), LLC. Mr. Chris Godfrey View
16-0001 Patriot Tank Lines Inc. Mark Mietz View
16-0017 LOGSA Packaging , Storage and Containerization Center Mr. Andrew Gesford View
15-0207 Department of Army Mr. Marco Boasso View
16-0004 Texas Department of Public Safety Trooper Kelly F. McClatchy View
16-0016 U.S. Customs and Border Protection Mr. Jason Hart View
16-0003 Mr. Richard Lloyd View
16-0002 Public Utilities Commission of Ohio Mr. Tom Forbes View
15-0231 A.S. Trust & Holdings Mr. Richard Maruya View
15-0155 UBH International Mr. Alex McGonagle View
15-0185 HDI Gauges Mr. Gary Rohn View
15-0243 Environmental Health & Safety Ms. Marilyn Winterburg View
16-0025 Pine Mr. Jason Miller View
16-0012 Patterson Companies, Inc Mr. Robb Boros View
16-0019 St. Johns County Utility Department Mr. Tony Cubbedge View
15-0142 Covington & Burling LLP. Mr. Thomas Brugato View
16-0006 Mr. Joseph Tsiyoni View
15-0237 Slide Products, Inc. Mr. Michael Muth View
15-0246 Petroleum Transport, Inc. Roger Kirk View