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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
14-0004 HMT Associates, L.L.C. Ms. Patricia Quinn View
13-0241 S.C. Johnson & Son, Inc. Ms. Georgia Barr View
14-0026 Working Solutions, Inc. Mr. Jay Davis View
13-0217 Mr. Mark B. Hawk View
14-0031 YRC Freight, Inc. Ms. Susan D. Camara View
14-0037 Patton Boggs LLP Ms. Carolina Medero View
14-0012 Mr. Adrian Shipman View
14-0003 Wiley Rein LLP Mr. George Kerchner View
13-0208 Avantor Performance Material, Inc. Dr. Donald R. Paulus View
14-0016 URS Corporation Mr. Andrew N. Romach View
12-0056R Reusable Industrial Packaging Association, MD Packaging Solutions LLC & Lawrence W. Bierlein, Esq. Mr. Paul W. Rankin, Mr. Dan Dengler & Mr. Lawrence W. Bierlein, Esq. View
14-0036 Department of Ecology Mr. Gerald French View
CHI-14-001 Reusable Industrial Packaging Association Paul W. Rankin View
CHI-14-0036 Washington State Department of Ecology Gerald French View
13-0236 Komatsu America Corporation Ms. Roxanna Marchand View
13-0124 URS corporation Mr. Andrew N. Romach View
13-0181 Northern Air Cargo, Inc. Mr. Mark Smith View
14-0021 Lufthansa Cargo the Americas Mr. Hilmar Leng View
13-0198 Hazwaste Packaging Consultants Mr. Robert White View
13-0051 Occidental Chemical Company Mr. Norman Dodson View
PI-12-0007 City of Bangor Mr. Paul Nicklas View
13-0207 Thompson Tank, Inc. Mr. David L. Thompson View
13-0185 Veolia ES Technical Solutions, L.L.C. Ms. Jennifer Eberle View
13-0052R Simpson Strong Tie Company, Inc. Densie Nguyen View
13-0228 HMT Associates, LLC Mr. E. A. Altemos View
13-0234 Strem Chemcials, Inc. Mr. Jason M. Stevens View
14-0005 Casa International Brokerage, Inc. Mr. Hector Casas View
13-0183 Alaska Airlines Mr. Mike Tobin View
13-0209 DuPont Global Logistics Mr. Kevin Greene View
13-0238 Veolia ES Technical Services LLC Mr. Richard Finnegan View
13-0189 JBE Enterprises Mr. Frank Hannah View
13-0224 Linde North America, Inc. Mr. Guy Dalton View
13-0226 Air Techniques, Inc. Mr. Michael Toole View
13-0213 Lockheed Martin MST Mr. Kevin Unger View
13-0230 Universal Well Services, Inc. Mr. Tom Cloud View
13-0201 Hedwin Corporation Ms. Cheryl Defelice View
13-0178 ThyssenKrupp North America, Inc. Mr. Michael J. Bauer View
13-0210 Baker Hughes Houston Technology Center Mr. James K. Elrod View
13-0186 UTi Ms. Kathryn Singer View
13-0229 C&E Dot compliance Consultants LLC Mr. Christopher Widman View
13-0221 3M Center Mr. William Gramer View
13-0146 FIBA Technologies Mr. Christopher Adams View
13-0164 Mr. Cesar Enrico View
13-0190 T-Aerospace, LLC Mr. Patrick Miller View
13-0191 Garland Welding Supply Mr. Andrew Simmons View
13-0223 Mr. William Briner View
13-0214 3M Mr. Todd Strobe View
13-0195 Public Utilities Commission of OhioTransportation Department Mr. Tom Forbes View
13-0192 Nynas USA, Inc. Mr. Edward Skelton View
13-0157 MHF Services Mr. William Dawson View