USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

49 CFR Parts 100-199

PHMSA has published several Frequently Asked Questions (FAQs) documents on programmatic topics. Please review these documents here at:

Additionally, OHMS has published Hazardous Materials FAQs based on letters of interpretation on the following topics:

OHMS: 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).

OPS: 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: 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.

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

Search the eCFR

Ref ID: Date Company Name Individual Name Response Document
01-0288 Clariant Corporation Mr. Robert F. Rau View
01-0289 Enefco International, LTD. Mr. James F. Timmins View
01-0290 URS Corporation Mr. Andrew Romach View
01-0292 World Logistic Group, Inc. Mr. Steve McKenna View
01-0294 Department of the Army Mr. William R. Frerichs View
01-0295 Girard Equipment, Inc. Mr. John Freiler View
01-0299 URS Corporation Mr. Andrew N. Romach View
01-0300 Alaska Abatement Corporation Mr. Arthur Solvang View
01-0302 Dinda and Associates, Inc. Mr. John F. Dinda, Jr. View
01-0303 Quay Equestrian Limited Mr. Andrew Stockford View
01-0304 The Sherwin Williams Company Ms. Sandra L. Basharn View
01-0305 Federal Motor Carrier Safety Administration William A. Quade View
01-0309 AirTran Airways, Inc. Mr. Gregory R. Curtis View
01-0313 IT Corporation Mr. Lee R. Wilmot View
01-0316 UPS Corporate Hazardous Ms. Mary Beth View
01-0317 Mr. Joseph Cleveland View
01-0318 Tempra Technology, Inc Mr. Martin Sabin View
01-0319 ECD Engineering Ms. Karen Schaaf View
01-0320 EnerSys Inc. Mr. Jeffrey S. Koller View
01-0321 Container Specialties Group Mr. Jake Mailey View
01-0324 Peerless Coatings, Inc. Ms. Sandra Via View
02-0005 Keehn Service Corporation Richard C. Willard View
02-0006 Railroad Commission of Texas Gas Services Division Richard L. Gilbert View
02-0011 Quadra Chemicals Western, Inc Edward Doheny View
02-0012 CrossNet USA, Inc Cindy Seki View
02-0013 SAIC Frederick Cancer Research Joseph P. Kozlovac, M.S., CBSP, RBP View
02-0016 Perry Wiltrout View
02-0017 Proco Incorporated Stephen M Hurst View
02-0021 Sharps Compliance Edward Krisiunas, MT (ASCP), CIC, MPH View
02-0023 Texas Commission on Fire Protection JonathanWeidemann View
02-0025 LPS Industries, Inc. Gary Flaherty View
02-0026 TEN-E Packaging Services, Inc Robert J. Ten Eyck View
02-0027 Calvert City, KY Emulsions Plant, Air Products & Chemicals A & Joe Campbell View
02-0029 Hazardous Materials Division, Federal Motor Carrier Safety Administration William Quade View
02-0030 Exopack Technical Lab Richard Ruebush View
02-0032 Elite Consumer Products Mark Chevrier View
02-0033 Timothy Roberts View
02-0035 Smurfit-Stone Container Corporation Richard M.Thomas View
02-0037 Dr. Arnel D. Potte View
02-0038 Paschall Track Lines, Inc. Melissa Houser View
02-0039 DCm DECOmetal International Trading GrnbH Maria Posch View
02-0040 GS Battery (U.S.A.) Inc. Greg DePies View
02-0043 R+L Carriers Dana Probasco View
02-0044 Zambelli Internationale Fireworks Mfg. Co. Inc. Ron Snyder View
02-0045 HB Fuller Company Gene Seco View
02-0047 RWE Solutions Stanley H. Hodges View
02-0048 Octel Starreon LLC. Ann MarieWilliams View
02-0050 Mr. William K. Taggart, CET Lion Technology, Inc View
02-0055 U.S. Department of Energy, Richland Operations Office Steven H. Wisness View
02-0056 Allied Universal Corp. Robin J. Eddy View

E.g., 02/09/2021
E.g., 02/09/2021
Part/Section Subject
177.840 Class 2 (gases) materials
177.841 Division 6.1 and Division 2.3 materials
177.842 Class 7 (radioactive) material
177.843 Contamination of vehicles
177.848 Segregation of hazardous materials
177.854 Disabled vehicles and broken or leaking packages; repairs
178.2 Applicability and responsibility
178.273 Approval of Specification UN portable tanks
178.274 Specifications for UN portable tanks
178.274 Specifications for UN portable tanks
178.275 Specification for UN Portable Tanks intended for the transportation of liquid and solid hazardous materials
178.277 Requirements for the design, construction, inspection and testing of portable tanks intended for the transportation of refrigerated liquefied gases
178.3 Marking of packagings
178.320 General requirements applicable to all DOT specification cargo tank motor vehicles
178.33 Specification 2P; inner nonrefillable metal receptacles
178.33-7 Wall thickness
178.33-9 Marking
178.337 Specification MC 331; cargo tank motor vehicle primarily for transportation of compressed gases as defined in subpart G of part 173 of this subchapter
178.337-1 General requirements
178.337-10 Accident damage protection
178.337-11 Accident damage protection
178.337-16 Testing
178.337-17 Marking
178.337-18 Certification
178.337-3 Structural integrity
178.337-8 Openings, inlets, and outlets
178.337-9 Pressure relief devices, piping, valves, hoses, and fittings
178.338-10 Accident damage protection
178.338-16 Inspection and testing
178.33a Specification 2Q; inner nonrefillable metal receptacles
178.33a-8 Tests
178.33b-5 Material
178.33b-7 Design qualification test
178.33b-9 Marking
178.345 General design and construction requirements applicable to Specification DOT 406 (178.346), DOT 407 (178.347), and DOT 412 (178.348) cargo tank motor vehicles
178.345-1 General requirements
178.345-10 Pressure relief
178.345-11 Tank outlets
178.345-14 Marking
178.345-15 Certification
178.345-2 Material and material thickness
178.345-3 Structural integrity
178.345-5 Manhole assemblies
178.345-7 Circumferential reinforcements
178.345-8 Accident damage protection
178.345-9 Pumps, piping, hoses and connections
178.346-3 Pressure relief
178.347 Specification DOT 407; cargo tank motor vehicle
178.347-1 General requirements