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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
06-0267 Healthcare Support Services Lisa Hardesty, MA, CHCC, HEM  View
06-0238 EnergySolutions Mr. James H. Portsmouth  View
06-0247 DelValCo Consultants Mr. George M. Thorpe View
06-0264 Intertek Caleb Brett Mr. William J. Cherepon View
06-0245 Reagent Chemical & Research, Inc. Mr. Robert Dritschel View
06-0254 Rite Aid Corporation Mr. Glenn A. Courtney View
06-0273 Piedmont Plastics, Inc. Mr. Dale Austin View
06-0271 Georgia Department of Public Safety Captain Bruce Bugg View
06-0248 Currie Industrial Services, LLC Mr. Allan B. Currie, Jr. View
06-0255 Energy Solutions Federal Services Mr. James Portsmouth View
06-0243 Alloy Custom Products Mr. Everett Snoeberger  View
06-0279 Wisconsin Propane Council Mr. Ronald Sutherland View
06-0253 Belshire Environmental Services, Inc. Mr. Larry Moothart View
06-0262 DOT Compliance Mr. Clark W. Elliot View
06-0242 Solvay Chemicals, Inc. Dr. Marc A. Feldman, CQM/OE  View
06-0244 Fisher Scientific
International, Inc. 		Mr. Gene Sanders View
06-0231 Millennium Rail, Inc. Mr. J. F. Moore View
06-0224 Rohm and Haas Company Ms. Carrie Wayne View
06-0256 REGSCAN, Inc. Mr. Russ Shanahan View
06-0233 Air-4Life, Ltd. Mr. Eric Kimel View
06-0235 Railroad Commission of Texas Mr. James T. Osterhaus  View
06-0240 H.C. Gabler, Inc. Mr. Robert L. Summers  View
06-0223 Minnesota Department of Transportation Mr. Michael Ritchie View
06-0225 City of Surprise, Water Services Department Ms. Christine Nunez View
06-0219 Jones Chemicals, Inc. Mr. D. L. Casmey View
06-0237 Ms. Dorothea A. Welk  View
06-0210 Dufour Petroleum LP Mr. Don Ladner View
06-0214 Industrial Health & Safety Consultants Ms. Denese Deeds View
06-0232 Premier Trading Group Mr. Dub Phillips View
06-0201 Oak Ridge National Laboratory Mr. Mark B. Hawk View
06-0212 Ameriflight, Inc. Mr. Matt Payne View
06-0229 National Headquarters Mr. Michael I. Gorman  View
06-0204 Mr. Jim Pitts View
06-0230 Wiley Rein & Fielding LLP Mr. George A. Kerchner View
06-0141 LG Chem/Mobile Energy Company Hyeong " Jin Kim, Ph.D.  View
06-0209 Prometheus International, Inc. Mr. Keith K. Park  View
06-0218 Holmes Freigth Lines, Inc. Mr. Mohamed R. Ali View
06-0194 North American Automotive Hazmat Action Committee Mr. Dave Madsen View
06-0196 Quarles & Brady LLP Mr. Lars E. Guibrandsen View
06-0208 ETCetera International, Inc Mr. Jim Anderson  View
06-0100 Department of Energy Mr. James M. Shuler View
06-0185 Ehrhart Propane Gas Mr. Thomas G. Overbaugh View
06-0180 HMT Associates, L.L.C Mr. E.A. Altemos  View
06-0166 American Pyrotechnics Association Mr. Gregg Smith  View
06-0160 Supervac 2000 Ms. Nathalie Doyon  View
06-0190 RWE NUKEM Corporation Mr. Stan Hodges View
06-0121 Hydrol Chemical Co., Inc. Mr. Richard W. Hoffman, Jr.  View
06-0216 Wiley Rein and Feuding LLP Mr. George A. Kerchner  View
06-0189 Nukem Corporation Mr. Stan Hodges View
06-0200 Mr. Robert D. Howerton, Ph.D. View