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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
11-0077 Minnesota State Patrol, District 4700 Sgt. Jay K. Sletten View
11-0103 Mr. Ed Van Schoick View
11-0049 EnergySolutions, Inc. Ms. Merrie Schilperoort View
11-0048 Container-Quinn Testing Laboratories, Inc. Mr. Stephen C. Powell View
11-0125 Mr. Hank Sheller View
11-0015 Mr. Richard Olson View
10-0195 National Oilwell Varco Jianke Wang, Ph.D., P.E. View
11-0110 Delta Air Lines, Inc. Mr. Rick Blenkush View
11-0169 Ropak Packaging Mr. Terry Iker View
11-0071 EnviroServe Mr. Larry Steigerwald View
11-0107 Chammas Cutter, Inc. Mr. Michael Chammas View
11-0111 Marv Golden Pilot Supplies Mr. Richard Golden View
11-0056 Raytheon Network Centric Systems Integrated Communication Systems Ms. Janette Parker View
CHI-10-0239 Village of Itasca Nicole P. Aranas View
11-0102 Texas Department of Public Safety Texas Highway Patrol/Commercial Vehicle Enforcement Mr. Patrick B. Zatopek View
PI-10-0026 New Mexico Public Regulatory Commission Mr. Jason Montoya, PE View
11-0117 Worthington Cylinders Mr. Steve Gentry View
11-0105 DuPont Sourcing & Logistics Mr. Thomas Reese View
11-0008 J.J. Keller and Associates, Inc. Mr. Thomas J. Ziebell View
11-0099 Johes-Blair Company Mr. Matt Barfknecht View
11-0032 RSLP, TASC Inc. Ms. Lisa Taylor View
PI-11-0100 New Penn Motor Express Mr. Thomas Gerhold View
11-0088 Honeywell International, Inc. Ms. Carrie Wayne View
11-0024 AkzoNobel Mr. Mark A. Connolly View
CHI-11-005 County of San Diego Tom Bosworth, Esq. View
CHI-11-002 County of San Diego Tom Bosworth View
11-0036 Cusco Fabricators, Inc. Mr. Sarathi Chilukuri View
PI-10-0018 Duke Energy Field Services, LP Mr. David Bohn View
PI-10-0022 Central Hudson Gas & Electric Corp. Mr. David W. Merte, P.E. View
11-0074 Currie Associates, Inc. Mr. Tom Ferguson View
11-0067 Airgas SAFECOR Mr. John Anderson View
10-0252 The Dow Chemical Company Ms. Cherry Burke View
11-0047 HMT Associates, L.L.C. Mr. Edward A. Altemos View
10-0116 NW Natural Mr. Neil Banman View
11-0002 Thompson Tank Inc. Mr. David Thompson View
11-0007 The Law Offices of Paul D. Borghesani Paul D. Borghesani View
CHI-11-004 Missouri Trucking Association Mr. Ronald D. Breau, CDS View
CHI-11-001 Missouri Trucking Association Ronald D. Breau View
09-0300 Sartorius Stedim Filters, Inc. Mr. José H. Braulio-Martinez View
11-0079 Mr. Roger W. Cooper View
PI-10-0015 Alta Mesa Services, LP Ms. Ronda Louderman View
10-0107 California National Guard U.S. Army Mr. Robert Morrow View
10-0066 FedEx Express Corporation Mr. David Littlejohn View
11-0070 DS Environmental Solutions Mr. Ricardo Guerra View
11-0021 Kajuligan Corporation Mr. Clifford Croft View
11-0038 Los Alamos National Laboratory Mr. Donald Thorp View
11-0072 AirSep Corporation Mr. Richard W. Boerdner View
11-0052 Honeywell Inc. Ms. Claire Matlon View
PI-11-0008 Northern Natural Gas Company Mr. Thomas Correll View
11-0078 Mr. Roger W. Cooper View