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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
14-0134 General Electric Ms. Bridgette A. Lobstein View
14-0117 Arkema, Inc. Ms. Christina Kurtz View
14-0176 CMV Inspector Mr. Gilbert Castro View
14-0115 Midwest Veterinary Supply, Inc. Ms. Joanne Kittridge View
15-0026 Arkema Inc. Ms. Christina Kurtz View
14-0167 Currie Associates, Inc. Mr. Tom Ferguson View
14-0194 S.C. Johnson & Son, Inc. Mr. Chris Kubicek View
14-0188 Alaska Air, SEADG Mr. Ron Fink View
PI-13-0010 City of Susanville Mr. Craig Platt View
14-0210 Brian Kurtz Trucking Ltd. Mr. David Skater View
PI-14-0020 Stoel Rives LLP (Eni) Ms. Ramona L. Monroe View
PI-14-0017 Air Products and Chemicals, Inc. Mr. Jody R. Arner View
PI-14-0022 Caelus Energy Alaska LLC Mr. J Patrick Foley View
14-0204 Lockheed Martin Space Systems Compnay, SWFLANT Ms. Amanda B. Foskey View
14-0181 Duke Energy Corporation Mr. Chuck Denny View
14-0198 Denton Police Department Mr. Wm. Scott Burson View
14-0191 Daniels Training Services Mr. Daniel Stoehr View
14-0245 Kajuligan Inc. Mr. Cliff Croft View
14-0209 BASF Corporation Mr. Gregory R. Knauf View
15-0002 Invacare Corporation Ms. Carol Vierling View
15-0017 Walmart Ms. Veronica Wilson View
14-0226 ARKEMA Inc. Ms. Christina Kurtz View
14-0206 Port of Tucson Mr. Bryan Slagle View
14-0180 Countryside Tank Mr. Joe Greving View
14-0220 Premium Environmental Services Mr. Tom Stone View
14-0239 Sun Chemical Corporation Ms. Amy fischesser View
14-0180 Countryside Tank Division of Iowa Steel Fabrication, LLC Mr. Joe Greving View
14-0158 Mr. Richard J. Lloyd View
14-0171 Institute of Makers of Explosives Ms. Cynthia Hilton View
PI-14-0005 California Public Utilities Commission Mr. Joseph P. Como View
14-0159 Anadarko Petroleum Corporation Mr. Rick Hall, CEP View
14-0213 Tufpak, Inc. Mr. Brian T. Wadlinger View
14-0207 Wiley Rein LLP Mr. George Kerchner View
14-0203 The Cryo Guys Mr. Mike Tomasek View
14-0228 URS Corporation Mr. Andrew Romach View
14-0232 Acro Trailer Company Mr. Christopher Foshe View
14-0163 Dentons US LLP Mr. James W. Rubin View
14-0211 Peroxy Chem Mr. Ralph Mikida View
14-0231 PPG- Comex Mr. Israel Villarello View
14-0187 SHISEIDO Group USA Ms. Diana Olivari View
14-0221 WTS, Inc. Mr. Brian Burns View
14-0197 Philips Respironics Ms. Collen Witt View
14-0174 Lufthansa Cargo Mr. Hilmar Leng View
14-0047 Sandler, Travis & Rosenberg, P.A. Mr. Mark Ludwikowski, Esq. View
14-0064 NitroxFox LLC Mr. John Fox View
14-0152 Space Information Laboratories Mr. Nick Pelster View
14-0142 Transportation Compliance Associates, Inc. Mr. Mike Alston View
14-0149 Mr. Armando Sancerni View
14-0189 Mitsubishi Motors North America Ms. Dawn Perry View
14-0162 Global Satellite Engineering Mr. Scott Walters View