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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
10-0099 Sporting Arms & Ammunition Manufacturers Institute, Inc. Mr. Rick Patterson View
10-0101 Jefferson Lab Thomas Jefferson National Accelerator Facility Mr. Thomas Briggs, PE View
10-0118 Fox Racing Ms. Jennifer Lucia View
10-0083 Chemical Sector Coordinating Council Mr. Dan Walters View
10-0090 Industrial Packaging Alliance of North America Mr. John McQuaid View
10-0100 Wilhelmsen Ships Service Mr. Dave Finlay View
09-0180 Burdette & Associates, Inc. Mr. Michael Burdette View
10-0088 Dyno Nobel, Inc. Mr. Mark Anderson View
09-0088 Roadrunner Rocketry, Inc. Mr. Bob Korman View
10-0068 FedEx Express Corporation Mr. David Littlejohn View
10-0103 Calfrac Well Services Corp. Mr. Dave Mykyte View
10-0076 Hyundai America Shipping Agency, Inc. Mr. Herb Giles View
10-0079 Air Liquide Industrial U.S. LP Mr. Steven Bilger View
10-0087 US Dynamics Corporation Mr. George Jantzen View
10-0085 Canadian Material Support Group Captain E.M. Steele View
10-0043 Gefahrgutberatung/Gefahrgutausbilding Mr. Jens-Thomas Rueckert View
10-0067 SDS, Inc. Mr. Stephen Nesteriak View
10-0075 Landstar Transportation Logistics Mr. Wes Pace View
09-0245 Mr. Andrew Abrams View
10-0084 Commercial Chemical Mr. David L. Turnage View
10-0054 National Oilwell Varco Dr. Jianke Wang View
09-0268 Dole Explosives, Inc. Mr. Samuel Dole View
09-0263R TEN-E Packaging Services, Inc. Mr. Robert Eyck View
05-0111R Reactives Management Corporation Ms. Cherie Walton View
10-0078 Reagent Chemical & Research, Inc. Mr. Robert Dritschel View
10-0071 Holland & Knight Law Firm Mr. Jonathan Epstein View
10-0039R Nuclear Diagnostic Products Mr. Ken Ali View
09-0220 Airspeed Press Mr. Steven Lindblom View
10-0061 Bozel LLC Ms. Kelley O'Connor View
09-0301 Tronox, LLC Mr. John Hatmaker View
10-0024 ATMI Mr. James McManus View
10-0065 TSO3, Inc. Mr. Jean-Martin Vallières View
09-0285 Mr. Brad Bockey View
10-0053 ATK Mr. Christopher J. Widman View
09-0305 Mr. James La Porte View
10-0050 United Airlines Ms. Nancy Finkenkeller View
10-0056 Custom Metalcraft, Inc. Mr. Clark Holden View
09-0209 INDSPEC Chemical Corporation Ms. Vicki H. Weightman View
10-0060 URS Corporation Ms. Erin Jarman View
10-0028 Total Reclaim, Inc. Ms. Peggy Halferty View
09-0281 FDSE, Inc. Mr. Matjaz Zakotnik View
09-0248 Dangerous Goods Advisory Council Mr. Frits Wybenga View
09-0118R HOYER Global Transport BV Mr. Peter Hordijk View
09-0128 Freight Runners Express, Inc. Mr. Patrick Hammer View
10-0064 URS Corporation Ms. Erin N. Jarman View
10-0034 Global Green Services, Inc. Ms. L'Gena Prevatt View
09-0109 Southern Resin, Inc. Mr. Allen Grubb View
10-0032 Energy Solutions Mr. James H. Portsmouth View
CHI-09-0089 Bob Craig View
09-0089 Mr. Bob Craig View