USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

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
07-0095 Mr. Rick Kite View
07-0167 Landmark Aviation Mr. Frederick W. Klein View
07-0170 American Cap Co. L.L.C Mr. Kerry Hricsina View
07-0176 Missouri Gas Energy Ms. Crystal Callaway View
07-0156 Dangerous Goods Advisory Council Mr. Michael Morrisette View
07-0137 Seaboard Marine, LTD Mr. John P. Plasencia View
06-0099 Security and Risk Management, the Americas Mr. James LoBello View
07-0160 Charkit Chemical Corporation Mr. Steve J. Catania View
07-0111 Dr. Lilly Langer View
07-0136 Bolds & Associates, LLC Mr. James J. Bolds      View
07-0116 Tatro Tekosky Sadwick LLP Mr. Steve R. Tekosky View
07-0173 Umicore USA, Inc Mr. Gary Sommer View
06-0280 ExxonMobil Chemical Company Mr. Ronald J. Stokes View
07-0034 Georgia Department of Public Safety Captain Bruce Bugg View
07-0150 Owner-Operator Independent Drivers Association, Inc. Mr. Kip Hough View
07-0026 American Electric Power Mr. Ray Wirt View
07-0124 Taylor Express, Inc. Mr. Roderick MacLean View
CHI-06-0085 The UPS Store Nancy Kasza-Scott View
06-0085 The UPS Store Ms. Nancy Kasza-Scott View
CHI-07-001 Hoagland, Fitzgerald, Smith & Pranaitis Stephen J. Maassen View
07-0067R Alcoa KAMA Mr. Chris Meeks View
07-0151 Hawkins, Inc. Mr. Chris W. Gibson View
07-0129 SESI Consulting Engineers Mr. John Nederfield View
07-0103 Greenberg Traurig, LLP Mr. Sanford M. Saunders, Jr, Mr. Kenneth P. Kaplan View
07-0146 Mr. Frank Milam View
06-0020 Trinity Industries, Inc. Mr. Greg McRae View
07-0029 TEN-E Packaging Services, Inc. Mr. Robert J. Ten Eyck    View
07-0123 Aug 13, 2007 Mr. Norman W. Briggs View
07-0148 Castaway Trash Hauling Mr. Steven Duque View
07-0065 National Oceanic & Atmospheric Administration Mr. Dan Poulos    View
07-0140 Advanced Chemcial Transports, Inc. Mr. James A. Castrodale, Jr View
07-0076R Natural History Museum Of Los Angeles County Mr. Leonard M. Navarro   View
07-0106 Cobasys Mr. Anthony J. Serventi View
07-0044 western Kentucky University Mr. Christopher J. Widman View
07-0127 Hazardous Materials Transportation Engineer Mr. Jerry A. Shipman View
07-0081 Pilot Chemical Company Mr. Matthew J. Leary View
07-0131 National Tank Truck Carriers, Inc. Mr. Thomas P. Lynch View
07-0133 Charkit Chemical Corporation Mr. Steve J. Catania View
07-0138 HAZ-MAT Transportation Services Mr. Jack Peters View
07-0113 Waste Technology Services, Inc. T.L. Nebrich. Jr., CHMM, QEP. REM View
07-0088 SAIC-Frederick, Inc. Ms. Shawn K. Brown  View
05-0235R Huntsman Clifford W. Lester, MSPH, CIH, EMT’B, DGSA View
07-0118 Northwest Airlines Inc. Mr. David A. Tikaisky View
06-0265 Hissong Kenworth-GMC, Inc. Mr. Jeff Reutter View
07-0091 Abbott Ms. Alicia Gaines View
07-0101 Degussa Corporation Mr. John Foglio View
07-0104 Raytheon Technical Services Company Mr. James Traylor  View
07-0094 MTS Medical Waste Management Mr. Edward Petrullo View
07-0098 Brenntag Southeast, Inc. Mr. Bruce Biehl View
07-0064 The Alpha Group Mr. Vince Panunzio View