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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
00-0137 Kovatch Corporation Mr. David Schappell View
00-0138 Corrugated Container Corporation Mr. John Byers View
00-0139 U. S. Department of Transportation Mr. Kent D. Fleming View
00-0141 Merichern Company Research Center Mr. Leo N. Richard Jr. View
00-0142 Radian International Mr. Andrew N. Romach View
00-0144 Midwest Rubber Mfg., Inc. Ms. Darlene Rank View
00-0146 Quality King Distributors, Inc. Mr. Ron Mihalek View
00-0147 Scenic Airlines, Inc. Mr. Tom O'Dell View
00-0148 Quality Control Department Mr. Colum O'Hara View
00-0149 Smurfit-Stone Container Corporation Mr. Steven Pfeiffer View
00-0152 Green Bay Packaging Inc. Mr. David Teames View
00-0153 Petroleum Transportation & Storage Association Mr. Mark S. Morgan, Esq. View
00-0154 Equistar Chemicals, L.P. Ms. Diedre J. Device View
00-0155 Frank's Gun & Pawn Mr. Frank Chamberlin View
00-0156 Russell-Stanley Mr. Earl Lind View
00-0157 Mr. John P. McGavis Mr. John P. McGavis View
00-0158 Lapoint Industries Lapoint Industries View
00-0159 Compliance and Response Management Mr. Henry Renfrew View
00-0162 United Van Lines, Inc. Mr. Michael Pfeiffer View
00-0163 IKI Manufacturing Co., Inc. Mr. Ken Johnson View
00-0164 Place Quick, Inc. Ms. Dianne Bechtold View
00-0166 All-Pak, Inc. Mr. R. C. Watt View
00-0168 Exxon Mobil Chemical Company Mr. Ronald J. Stokes View
00-0170 Stonhard, Inc. Mr. Walter D. Toomer, CHMM View
00-0172 MedCenter Air Mr. Michael Keller View
00-0173 Standards Development, OHM-II Delmer F. Billings, Chief View
00-0176 Ogletree, Deakins, Nash, Smoak & Stewart, P.C. Mr. David E. Jones View
00-0180 Gander Chemical Company, Inc. Mr. Robert Keel View
00-0181 Samson Tug and Barge Company, Inc. Mr. Al Snelling View
00-0182 U. S. Department of Labor Mr. John P. Seiler View
00-0184 LaRoche Industries, Inc. Mr. Carlton W. Hendrix View
00-0185 Overnite Transportation Company Mr. Garry Howell View
00-0186 Oakite Products, Inc. Mr. Barry L. Dance View
00-0188 Morgan Schaffer System Mr. Eric Valentine View
00-0189 Specialized Transport Repair Mr. John P. McGavis View
00-0190 Design Certifying Engineer Mr. David Fellows View
00-0191 International Paper Mr. Richard Ruebush View
00-0192 Department of Public Safety Mr. C.D. Lavender View
00-0193 Hazardous Materials Advisory Council Mr. Vaughn Arthur View
00-0194 Linscot Enterprises, Inc. Ms. Linda Terry View
00-0195 AGWORKS, Inc Ms. Esmeralda Garcia View
00-0196 Tandem Technologies International Mr. R. Jett Rich View
00-0197 Barlen and Associates, Inc. Mr. William Barlen View
00-0199 Florida Department of Environmental Protection Ms. Irene Gleason View
00-0200 GEM Technologies, Inc. Mr. Stephen B. Dzialo, Sr., PE View
00-0201 Regulatory Compliance Services Mr. Chris Corea View
00-0203 Mr. Kenneth Ozard View
00-0205 Mr. Steve Starbuck Jacobs Engineering Group, Inc. View
00-0206 Alaska Airlines Ms. Marilyn Dirkx View
00-0210 Research Products, Inc.of Alabama Mr. Doug Martin View

E.g., 02/09/2021
E.g., 02/09/2021
Part/Section Subject
172.423 DANGEROUS WHEN WET label
172.427 ORGANIC PEROXIDE label
172.430 POISON label
172.442 CORROSIVE label
172.446 CLASS 9 label
172.447 LITHIUM BATTERY label
172.500 Applicability of placarding requirements
172.502 Prohibited and permissive placarding
172.503 Identification number display on placards
172.504 General placarding requirements
172.505 Placarding for subsidiary hazards
172.506 Providing and affixing placards: Highway
172.508 Placarding and affixing placards: Rail
172.510 Special placarding provisions: Rail
172.512 Freight containers and aircraft unit load devices
172.514 Bulk packagings
172.516 Visibility and display of placards
172.519 General specifications for placards
172.522 EXPLOSIVES 1.1, EXPLOSIVES 1.2 and EXPLOSIVES 1.3 placards
172.532 FLAMMABLE GAS placard
172.540 POISON GAS placard
172.542 FLAMMABLE placard
172.544 COMBUSTIBLE placard
172.546 FLAMMABLE SOLID placard
172.550 OXIDIZER placard
172.554 POISON placard
172.556 RADIOACTIVE placard
172.558 CORROSIVE placard
172.560 CLASS 9 placard
172.600 Applicability and general requirements
172.602 Emergency response information
172.604 Emergency response telephone number
172.606 Carrier information contact
172.700 Purpose and scope
172.701 Federal-State relationship
172.702 Applicability and responsibility for training and testing
172.704 Training requirements
172.800 Purpose and applicability
172.802 Components of a security plan
172.804 Relationship to other Federal requirements
173.1 Purpose and scope
173.10 Tank car shipments
173.11 Exceptions for shipment of light bulbs containing hazardous materials
173.115 Class 2, Divisions 2.1, 2.2, and 2.3-Definitions
173.116 Class 2-Assignment of hazard zone