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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
08-0109 Lawrence W. Bierlein Lawrence W. Bierlein View
08-0065 ERM, Inc. Mr. Mark Yannett View
08-0038 Materials Handling Group, Inc. Mr. Jeffrey M. Welsh View
08-0048 Carolina Filters, Inc. Mr. Morgan Campbell View
07-0199 Department of Defense Explosive Safety Board Mr. Curtis M. Bowling View
08-0045 Kubota Manufacturing of America Mr. Brian Arnold View
08-0013 Idaho State Police Mr. Thomas Wright View
08-0052 ILS Manager - Aircraft Mr. Greg Hardwick View
08-0006 SIEMENS Building Technogies, Inc. Mr. Adam Jablonski View
08-0035 BD Medical - Medical Surgical Systems Mr. Lane Arbittier View
08-0041 Sweetser & Associates Mr. Larry D. Sweetser, Jr. View
08-0030 MaxPower, Inc. Mr. Frank H. Cassel View
08-0049 Los Alamos National Laboratory Ms. Lorelei Johnson View
07-0223 U.S. Battery Manufacturing Company Mr. Terry Campbell View
07-0236 Northern Air Cargo Mr. Mark Smith View
07-0233 Northern Air Cargo Mr. Mark Smith View
07-0232 Alaska Airlines, Inc. Mr. Michael Tobin, CHMM View
07-0174 Citronix, LP Mr. Chris A. DuBois View
08-0066 Montana Motor Carrier Services Enforcement Division Lt. Jeff McLaughlin View
07-0228 Brenner Tank LLC Mr. Nick Paulick View
07-0061 LIST Company, Inc. Mr. Rob Latham View
08-0023 U.S. Department of Energy Ms. Ella McNeil View
07-0234 Spectrum Brands, Inc. Ms. Tracy Staidi Wrycha View
08-0031 UT Southwestern Medical Center Dr. Frank H. Wians, Jr. View
07-0221 R+L Carriers Shared Services, LLC Ms. Tina S. Breezley View
07-0142 CMA CGM (America), Inc. Mr. Kevin Reposa View
08-0010 D.B. Western, Inc. - Texas Mr. Phil Johnson View
07-0147 Fort Vale Engineering Ltd. Mr. Dave Bailey View
07-0189 Dangerous Goods Advisory Council Mr. Frits Wybenga View
07-0219 Innovative Safety Solutions, Inc. Mr. Albert Calkin View
07-0144 General Environmental Management, Inc. Mr. Alexander Amort View
08-0042 Hamilton Sundstand Mr. Tom Magennis View
08-0018 Airgas-SAFECOR Mr. John Anderson View
07-0235 Petroleum Transportation & Storage Association Mr. Mark Morgan, Esq. View
07-0200 Republic Airways Holdings, Inc. Mr. Tom Ausbury View
07-0212 Georgia Department of Public Safety Capt. Bruce Bugg View
08-0027 Hawkins, Inc. Mr. Chris W. Gibson View
08-0002 Kajuligan Corporation Mr. Clifford E. Croft View
06-0260 D.J.'s Truck Repair, Inc. Mr. David Jones View
07-0126 REZ-1, Inc. (Boston) Mr. Mike Stern View
08-0019 Mr. Charles W. Guthrie View
08-0025 HMT Associates, L.L.C. Mr. E.A. Altemos View
08-0037 Allied Universal Corporation Mr. Robin J. Eddy Bolte View
07-0217 Advance Engineered Products, Ltd. Mr. Rattan Bahia View
07-0225 Packaging Applications for Dangerous Goods, LLC Mr. David Gluntz View
08-0017 NRS Logistics Mr. David Hiromura View
07-0230 Pipe Recovery Systems, Inc. Mr. Michel Chammas View
08-0015 Fed Ex Freight Ms. Sandra Richesin View
07-0208 American Metals & Chemical Corporation Mr. Barry D. Reichenberg View
07-0194 HAZMATEAM, Inc. Mr. Paul J. Dambek View