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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
16-0093 Broadcom Limited Mr. Richard Laudano View
16-0189 CTI and Associates, Inc. Ms. Terri Zick View
16-0184 Mr. Eric Fishman View
17-0006 Baker Hughes Mr. Joseph Murphy View
17-0001 MIdway USA Mr. Bradley Spears View
17-0011 Alchem Chemical Company Mr. Johnny Johnson View
16-0168 OneCIS Insurance Company Mr. Ed Whittle View
17-0015 Mr. Richard Lloyd View
16-0187 Swagelok Northern California Mr. Cameron Banks View
16-0150 Entegris Mr. John Gaudreau View
16-0205 W. T Bell International Inc. James Rairigh View
16-0170 Bancroft Hinchey Ltd Mr. Chris Hinchey View
16-0188 Propetro Tony Garcia View
16-0054 Infotrac, Inc. Mr. Jason Kob View
16-0172 DGI Training Mr. Sean Kelly View
16-0155 Baker Hughes Mr. Keegan Ritchie View
16-0009 Innovative Safety Solutions, Inc. Mr. Albert Calkin View
16-0176 SGS Petroleum Service Corporation Mr. Glenn Gillaspia View
16-0010 Mr. Jason Miller View
16-0111 MansourGavin, LPA Mr. Jeffrey Embleton, Esq View
16-0160 URS Corporation Mr. Andrew Romach View
17-0013 Berlin Packaging Gary Lindsey View
16-0143 Mr. Mark Hawk View
16-0200 Teleflex Mr. Jay White View
16-0118 Public Utilities Commission of Ohio Mr. Tom Forbes View
PI-15-0010 Alaska Gasline Development Corporation Mr. Keith Meyer View
16-0123 Scopelitis, Garvin, Light, Hansen & Feary, P.C. Timothy Wiseman View
16-0117 Pioneer Tank Lines, Inc. Mr. Larry Nielsen View
16-0171 Alaska Airlines, Inc. Mr. Mike Tobin View
16-0133 Mr. Mark Hawk View
16-0208 Enoch Kever PLLC Mr. Rod Johnson View
16-0139 Bureau Veritas Mr. Edgar Whittle View
16-0179 Mr. Dustan Burkey View
16-0085R Office of Motor Vehicle Enforcement Captain Dean House View
16-0163 USARC ARIMD Mr. William Rogers View
16-0134 Boston University Medical Campus Mr. Michael P. Walen Jr, MS, CHP View
16-0022 EMC Corporation Mr. Kendall Wilcox View
16-0097 HMT Associates, L.L.C. Mr. EA Altemos View
16-0141 AREVA, Inc. Mr. Glenn Mathues View
16-0147 Qantas Mr. Neil Smith View
16-0151 HazMat Resources, Inc. Mr. Daniel Shelton View
16-0056 Public Utilities Commission of Ohio Mr. Tom Forbes View
16-0144 ERM Scott Porter View
16-0120 OneCIS Insurance Company Mr. Frank Hamtak View
16-0157 Regulatory Resources Inc. Mr. W A Winters View
PI-16-0007 Ms. Jill S. Pierce Bradley Steele and Pierce, LLP View
16-0177 Robinson Nevada Mining Company Mr. Matt Thompson View
PI-16-0014 Lengert and Raiders LLC Mr. Rich Raiders View
16-0090 Texas Trailer Corporation Mr. Ray Williams View
16-0092 Mr. Richard Lloyd View