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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
14-0245 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
14-0220 Premium Environmental Services Mr. Tom Stone View
14-0180 Countryside Tank Mr. Joe Greving 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
14-0213 Tufpak, Inc. Mr. Brian T. Wadlinger View
14-0207 Wiley Rein LLP Mr. George Kerchner View
14-0159 Anadarko Petroleum Corporation Mr. Rick Hall, CEP 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
14-0221 WTS, Inc. Mr. Brian Burns View
14-0231 PPG- Comex Mr. Israel Villarello View
14-0187 SHISEIDO Group USA Ms. Diana Olivari View
14-0211 Peroxy Chem Mr. Ralph Mikida View
14-0174 Lufthansa Cargo Mr. Hilmar Leng View
14-0197 Philips Respironics Ms. Collen Witt 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
14-0189 Mitsubishi Motors North America Ms. Dawn Perry View
14-0183 Denton Police Department Mr. William Burson View
14-0149 Mr. Armando Sancerni View
14-0162 Global Satellite Engineering Mr. Scott Walters View
14-0141 Innovage, LLC Mr. Ron Van Bavel View
PI-14-0013 Michigan Public Service Commission Mr. David J. Chislea View
14-0154 Pitt Ohio Mr. Timothy L. Stipcak View
14-0098 Complete Compliance Services Mr. Len Satkowski View
PI-14-0012 Williams West, Gas and Liquids Mr. Jared Ellsworth View
14-0153 Deitrich Engineering Mr. David Deitrich View
14-0058 Transportation Systems Solutions Mr. Peter Olsen View
14-0139 Linde Gas North Mr. Guy Dalton View
14-0160 North America Dangerous Cargo (Maersk) Mr. Charles A. Giglia View
14-0173 Sika Corporation USA Mr. Arthur Van Houten View
14-0128 University of Minnesota Mr. Michael Maurer View
14-0071 Willaims International Mr. Stan Harrison View
14-0089 URS Corporation Mr. Andrew Romach View
PI-14-0007 Duke Energy Florida Mr. Reginald Anderson View
PI-14-0006 Mr. Mark C. Wiggin Brooks Range Petroleum View
14-0018 URS Corporation Mr. Andy N. Romach View