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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
03-0172 Ondeo Nalco Company Ms. Anita S. Knight View
03-0278 URS Corporation Mr. Andrew N. Romach View
04-0033 PPG Industries, Inc. Mr. Gordon W. Rousseau View
03-0311 Mr. Joseph Sanok View
CHI-04-001 Agricultural Retailers Association Richard Gupton View
03-0326 Kansas State University Mr. Mitch Ricketts, CSP View
04-0013 Keller and Heckman LLP Mr. Michael P. Morrone View
04-0014 Jet-Lube, Inc. Mr. Donald A. Oldiges View
04-0004 ATK Alliant Teclisystems Mr. Christopher J. Widinan View
04-0161 URS Corporation Mr. Andrew N. Romach View
03-0318 Hyundai America Shipping Agency, Inc. Mr. Herbert Giles View
03-0277 Leak Location Services, Inc. Mr. Daren L. Laine View
04-0015 Jevic Transportation Mr. Samuel V. Yardurnian View
CHI-04-007 Harsco Corporation Russel S. Swanger, Jr., Esq. View
03-0325 Horizon Lines, LLC Mr. Cliff Bartley View
03-0321 Fisher Scientific Company, LLC Mr. John G. Mayfield View
03-0241 Metropolitan Water District of Southern California Ms. Carol Kaufman View
04-0022 Department of the Army
Military Surface Deployment and Distribution Command Operations Center 		Major Mark P. Wyrosdick View
03-0297 Sure-Way Systems, Inc. Mr. Gary Chilcott View
03-0291 Unilever Home & Personal Care - USA Ms. Teresa L. Medley View
03-0301 National Cargo Bureau, Inc. Captain Sam Rogers View
03-0300 Spray Chern Chemical Company Mr. Cliff Jacobson View
03-0148 Horizon Lines Mr. Cliff Bartley View
PI-04-0100 Marathon Ashland Pipe Line LLC Mr. Tad Schell, P.E. View
PI-04-0101 Dominion Transmission, Inc. Mr. Martin C. Schwoeble View
CHI-04-006 U.S. Department of Agriculture Mr. Wesley Throop View
03-0273 Texas Propane Gas Association Ms. Jackie R. Richards View
03-0236 United Dispatch of Iowa Inc. Mr. Bob Adams View
03-0302 Anitox Corporation Ms. Linda Isbill View
03-0290 360 Training Mr. Saif Fatteh View
03-0289 Mr. Elbert W. Muncy, Jr. View
03-0189 Varn International Ms. Lee Tipton View
03-0217 Southern International, Incorporated Mr. Terry L. Brittenham View
03-0007 Refrigeration Supplies Distributor Mr. Neill Boutilier View
03-0308 Mr. Frank Brockmann View
03-0267 Cosmo International Corporation Ms. Patricia M. Sobel View
PI-03-0108 Southwest Gas Corporation Mr. James F. Wunderlin, P.E. View
03-0256 The RxFire Company Mr. Peter Nopper View
03-0232 ABX Air, Inc. Ms. Karen Schatzmann View
04-0133 National Propane Gas Association Mr. Philip A. Squair View
02-0006 Railroad Commission of Texas Gas Services Division Richard L. Gilbert View
03-0242 Morris County Municipal Utilities Authority Ms. Laura MacPherson View
03-0198 Heritage Environmental Services Mr. David E. Blair View
03-0033 Nebraska State Patrol Bradley A. Wagner, Sergeant View
03-0285 Blue Rhino Corporation Mr. Richard J. Arthur View
03-0201 Gulf Trading (Alabama), Inc. Mr. Mark Walker View
03-0328 The Fertilizer Institute Mr. Kraig R. Naasz, President View
PI-03-0107 DOT Compliance Coordinator Enterprise Products Operating L.P. Mr. Mark J. Cartwright View
03-0251 URS Corporations Mr. Andrew N. Romach View
03-0265 The Daniels Corporation Ms. Terry Grimmond View