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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
08-0100 Hamilton, Miller & Birthisel, LLP Mr. Jules V. Massee View
08-0088 Mr. Merle M. Schnackenberg View
08-0050 Bell, Boyd & Lloyd, LLP Mr. Thomas R. Carey View
08-0044 Inspecorate America Corporation Mr. John E. Williams III View
08-0064 Saybolt LP Mr. Mike Conroy View
08-0145 Veolia Environmental Services Ms. Jennifer Eberle View
08-0146 L-3 Vertex Aerospace LLC Mr. Stephen W. Miller View
08-0160 Mr. John H. Hawn View
08-0163 ACCO Brands Corporation Mr. Darren Lenox View
08-0154 Symmetricom Mr. Gerald M. Beauchesne View
08-0114 packgen Corporation Mr. Russell Keith View
08-0120 Direcorate of Logistics Mr. William H. Orth III View
08-0139 URS Corporation Ms. Erin N. Jarman View
08-0138 Polymerics, Inc. Mr. William R. Sanderson View
08-0129 Volunteer Drum Mr. Jack Oody View
08-0127 Ecolab, Inc. Mr. Stephen V. Schulte View
08-0105 Vital Diagnostics Ms. Hardy View
08-0126 Austin Powder Company Mr. Larry J. (Scooter) King View
08-0142 Mr. Larry A. Berg Celtech Corporation View
08-0032 Invacare Corporation Ms. Carroll Martin View
08-0054 Paxton Company Mr. George Plum View
08-0099 DPC Industries, Inc. Ms. Charlcye Sells View
08-0046 Mr. Stanley Peterburgsky View
08-0124 Dist-Trans Company Mr. Daniel Raver View
08-0131 Allied Universal Corporation Ms. Robin E. Botle View
08-0051 Phillips Medical Systems Mr. Alan Greenstein View
08-0055 U.S. Department of Energy Ms. Ella McNeil View
01-0054R Georgia Department of Public Safety Captain Bruce Bugg View
08-0067 Interstate Battery System of America, Inc. Mr. Dan Lane View
08-0094 Reeves Construction Company Mr. Ray Couture View
08-0128 North American Transportation Consultants, Inc. Mr. JP Gibbons View
08-0103 Anodamine, Inc. Mr. Paul R. Hattingh View
08-0104 LPS Industries Mr. Gary Flaherty View
08-0078 Covance Laboratories, Inc. Ms. Dee Kaiser View
08-0092 Woodard and Curran, Inc. Mr. Kelly V. Camp View
08-0115 Mr. Roy A. Parker, Ph.D. View
08-0096 Sutherlands Ms. Tara Higgins View
08-0087 Idaho State Police Mr. Jim Eavenson View
08-0056 Imperial Freight Brokers, Inc. Mr. Robert A. Becker View
08-0108 Brenntag Mid-South, Inc. Mr. A.B. Eargood View
08-0093 Woodard & Curran Ms. Kelly V. Camp View
08-0086 EnerSys Mr. Tom Biello View
08-0082 Hydro-Test Products, Inc. Mr. Tom Sauta View
08-0012 Utah Division of Radiation Control Mr. Boyd Imai View
06-0274 HMTC Training & Consulting Mr. Philip C. Rieke View
08-0003 Transportation Skills Programs, Inc. & Hazardous Materials Publishing Co., Inc. Mr. Robert J. Keegan View
08-0060 Cryogenic Equipment and Services, LLC Mr. John D. Upperman View
07-0132 HMT Associates L.L.C. Mr. E. A. Altemos View
08-0043 Texas Railroad Commission Mr. James Osterhaus View
07-0031 West-Mark Mr. Gary Spoelstra View