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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
14-0005 Casa International Brokerage, Inc. Mr. Hector Casas View
13-0234 Strem Chemcials, Inc. Mr. Jason M. Stevens View
13-0209 DuPont Global Logistics Mr. Kevin Greene View
13-0189 JBE Enterprises Mr. Frank Hannah View
13-0238 Veolia ES Technical Services LLC Mr. Richard Finnegan View
13-0213 Lockheed Martin MST Mr. Kevin Unger View
13-0224 Linde North America, Inc. Mr. Guy Dalton View
13-0226 Air Techniques, Inc. Mr. Michael Toole View
13-0201 Hedwin Corporation Ms. Cheryl Defelice View
13-0178 ThyssenKrupp North America, Inc. Mr. Michael J. Bauer View
13-0230 Universal Well Services, Inc. Mr. Tom Cloud View
13-0210 Baker Hughes Houston Technology Center Mr. James K. Elrod View
13-0186 UTi Ms. Kathryn Singer View
13-0146 FIBA Technologies Mr. Christopher Adams View
13-0229 C&E Dot compliance Consultants LLC Mr. Christopher Widman View
13-0221 3M Center Mr. William Gramer 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
13-0192 Nynas USA, Inc. Mr. Edward Skelton View
13-0195 Public Utilities Commission of OhioTransportation Department Mr. Tom Forbes View
13-0148 NACA Logistics (USA), Inc. Mr. Eric Fischer View
13-0160 The Boeing Company Mr. Paul Burroughs View
13-0157 MHF Services Mr. William Dawson View
13-0137 Western Sales and Testing, Inc. Mr. Mark Griffin View
13-0188 Legend, Inc. Mr. Don Collier View
13-0197 Bemis Company, Inc. Mr. Andrew Petersen View
13-0163 Green Bay Packaging Inc. – Fremont Divisio Mr. Lance Lycourt View
13-0150 Fowler Transportation Ltd. Mr. Kevin Riley View
13-01637 National Association of Chemical Distributors Ms. Jennifer Gibson View
13-0187 Westpak, Inc. Mr. Pal Khangaldy View
PI-13-0006 Ms. Shelley Ragsdale View
13-0205 Reid laboratories LLC Mr. Scott Hopkins View
13-0196 Select Sire Power, Inc. Mr. Mark Carpenter View
13-0176 HSB Global Standards Mr. Oberst Mulet View
13-0180 Mr. Tom Alexander View
13-0172 Attorney at Law Mr. Lawrence W. Bierlein View
13-0035 Con-Way Truckload Mr. Jeff Messer View
11-0274R Department of the Army Ms. Sarah Gedrich View
13-0143 Mr. Joe Calonge View
13-0129 Lockheed Martin Corporation Ms. Mary P. Morningstar View
13-0159 Albermarle Corporation Mr. Brad Thomas View
13-0084 Chevron Products Company - Chevron Salt Lake Refinery Mr. Denton L. Schantz View
13-0168 Sandler, Travis & Rosenberg, P.A. Mr. Mark Ludwikowski View
13-0184 Coda Energy Mr. Chris Aragon View
13-0182 LabelMaster Services Mr. Robert Richard View
13-0173 KIK Custom Products - Classic Division Ms. Stacey Gorka View
PI-13-0004 Colorado Springs Utilities Mr. Mason Parsaye View