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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
PI-16-0014 Lengert and Raiders LLC Mr. Rich Raiders View
16-0177 Robinson Nevada Mining Company Mr. Matt Thompson View
16-0092 Mr. Richard Lloyd View
16-0166 Halliburton Mr. Albert Vandeaver View
16-0090 Texas Trailer Corporation Mr. Ray Williams View
16-0148 XPO Logistics Freight (XPOLTL) Ms. Marie Easley Cook View
16-0154 TEN-E Packaging Services Inc. Mr. Robert TenEyck View
16-0102 Amerflight Mr. Matt Payne View
16-0173 Andax Industries LLC. Mr. Patrick McAtarian View
16-0162 Roe Transportation Enterprise Mr. Rick Burkhead View
16-0130 One CIS Insurance Company Mr. Edgar Whittle View
16-0164 Groupe Robert Ms. Anais de Lausnay View
16-0182 Tom Dunaway and Associates, Inc. Mr. Tom Dunaway View
16-0130 One CIS Insurance Company Edgar A. Whittle View
16-0096 Mr. Douglas Shaw View
16-0156 Veolia North America Ms. Jennifer Eberle View
16-0140 Fuchs Lubricants Co. Mr. Tony Celo View
16-0095 Jamestown Container Corporation Mr. Brian Storms View
15-0187R Florida Highway Patrol Lieutenant Bryan Gay View
16-0153 Emergency Response and Training Solutions Mr. Ed Ballash View
16-0106 Global Logistics Ms. Julie Brown View
16-0020 Nebraska State Patrol Sgt. Brad Wagner View
16-0149 Tower Products, Inc. Ms. Caron Anderson View
15-0139 A.I.D. Inc. Mr. Donald Brittingham View
16-0146 DuBois Chemical, Inc. Mr. Jay Polk View
16-0107 HMT Associates, L.L.C. Mr. Andy Altemos View
PI-16-0012 Minnesota Department of Public Safety Mr. Jonathan C. Wolfgram View
16-0112 Atlantic Ro-Ro Carriers, Inc. Mr. Andrei Lazourenko View
15-0031R Mr. Joe Connelly View
15-0229R Idaho State Police Mr. Thomas Wright View
16-0079 Patterson Companies, Inc. Mr. Robb Boros View
16-0128 Cimarron Oil LLC Mr. Anthony Rausin View
16-0099 Veolia North America Jennifer Eberle View
PI-16-0009 Mr. Jonathan C. Wolfgram Minnesota Department of Public Safety View
16-0089 Label Solutions, Inc. Ms. Tammy King View
16-0109 Spectrum Techniques Mr. Daniel Sims View
15-0044 Northern Air Cargo Mr. Mark Smith View
16-0158 PRI International, Inc. Mr. Vincent Vitollo View
16-0083 NGL Crude Logistics, LLC. Mr. Don Robinson View
16-0055 AZKO Nobel Services, Inc. Mr. Mark Connolly View
16-0131 Alabama Power Ms. Sharon Trippany View
16-0136 DuPont Corporation Center for Safety, Health, and Environment (SHE) Mr. Kevin Greene View
16-0023 Williams International Mr. Stan Harrison View
16-0024 Williams International Mr. Stan Harrison View
PI-15-0014 Petersen Engineering Mr. J. Douglas Lindsay View
PI-16-0008 Maverick International, LTD Mr. Jerry Nelson View
16-0129 National Cargo Bureau Mr. Edward Walker View
16-0100 Potash Corp. Mr. Tracey Smith View
16-0069 Brenntag North America, Inc. Mr. Bruce Biehl View
16-0088 Landstar Transportation Logistics, Inc. Mr. Wes Pace View