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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
08-0224 Strem Chemicals, Inc. Mr. Jason Stevens View
08-0170 Oklahoma LP Gas Administration Mr. W.A. Glass View
08-0178 ExxonMobil Chemical Company Mr. Ronald J. Stokes View
08-0221 URS Corporation Ms. Erin N. Jarman View
08-0208 Baker Petrolite Corporation Mr. Aubrey R. Campbell View
08-0084 Transportation Development Group Mr. Jim Powell View
08-0095 OxySure Systems, Inc. Mr. John M. Lansdown View
08-0080 Idaho State Police Mr. Thomas R. Wright View
08-0200 Shane Havoc Consulting, LLC Mr. Gregory Sutherland View
08-0011 Digital Innovations Mr. David Martin View
08-0212 International Logistics Brown-Forman Corporation Ms. Christy Larimore View
08-0144 Local Hazardous Waste Management Program in King County Public Health, Seattle & King County Mr. Garrett Turner View
08-0172 National Electrical Manufacturers Association Mr. Craig Updyke View
08-0132 Idaho State Police Mr. Thomas Wright View
08-0177 Charkit Chemical Corporation Mr. Steve Catania View
08-0135 Safety & Compliance Associates, Inc. Mike Lopez, JD View
08-0195 LaMotte Co. Ms. Irene Penfield View
08-0176 Garvin, Light, Hanson & Feary Attorneys At Law Mr. Timothy W. Wiseman View
07-0209 Industrial Packaging Alliance of North America Mr. John A. McQuaid View
08-0193 URS Corporation Ms. Erin N. Jarman View
08-0125 HazMat Resources, Inc. Mr. Daniel G. Shelton View
08-0141 URS Corporation Ms. Erin Jarman View
08-0188 North Bay Enterprises, Inc. Mr. Achim K. Gartmann View
08-0184 Department of the Army, USAMC LOGSA Packaging Storage and Containerization Center Ms. Charlotte A Lent View
08-0057 Jacksonville Port Authority (Jaxport) Mr. Mike Becker View
08-0112 Southwest Electronic Energy Corp.                                      Mr. Randy Tanner                                            View
08-0173 Cannondale Sports Group Mr. Zach Krapfl View
08-0143 Hawkins, Inc. Mr. Chris W. Gibson View
08-0182 ACCO Brands Corporation Mr. Darren Lenox View
08-0098 HazMat Resources, Inc. Mr. Danny Shelton View
08-0186 Altair Nanotechnologies, Inc. Mr. Jeffrey A. McKinney View
08-0168 Hach Company Ms. Linda Wenger View
08-0089 3M Package Engineering, 3M Sourcing Operations Mr. William Gramer Specialist View
08-0161 Portable Rechargeable Battery Association Mr. George Kerchner View
08-0059 The Fertilizer Institute Ms. Pam Guffain View
08-0136 German Airforce FTC Mr. Egon Weyel View
08-0175 GEO Specialty Chemicals Mr. Matt Beasley View
08-0157 HMT Associates, L.L.C. Mr. E.A. Altemos View
07-0147R Fort Vale Engineering Limited Mr. Dave Bailey View
08-0118 Seaboard Marine Ltd. Mr. John Plasencia View
08-0075 Terumo Heart, Inc.                                                           Mr. Keith Proctor                                                                             View
08-0130 Thermo Fisher Scientific Mr. Gene Sanders View
08-0162 Montvale Cares, Inc. Ms. Pamela Smith View
08-0165 Black Forest Marketing, LLC Mr. Tom Leftwich View
08-0166 Remington Arms Company, Inc. Mr. Gregory D. Kehrli View
08-0106 Roeder Cartage Company, Inc. Mr. Robert Mitchell View
08-0028 Raytheon Missile Systems Mr. Steve Jacob View
08-0079 Washington Closure Hanford Mr. G.J. Borden View
08-0147 ComSonics, Inc. Mr. Daniel Brown View
08-0159 Alaska Air Group, Inc. Mr. Mike Tobin View