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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 (FAQ) documents on regulatory topics. Please review our FAQ documents here:

This section of the website provides the ability to find regulations information including regulations parts, content of sections, and interpretations for regulations sections. Below is a list of parts, identified by the part number and subject. 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.

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.

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

E.g., 02/09/2021
E.g., 02/09/2021
Part/Section Subject
175.8 Exceptions for operator equipment and items of replacement
175.9 Special aircraft operations
176.1 Purpose and scope
176.116 General stowage conditions for Class 1 (explosive) materials
176.118 Electrical requirement
176.140 Segregation from other classes of hazardous materials
176.144 Segregation of Class 1 (explosive) materials
176.170 Transport of Class 1 (explosive) materials in freight containers
176.172 Structural serviceability of freight containers and vehicles carrying Class 1 (explosive) materials on ships
176.200 General stowage requirements
176.27 Certificate
176.3 Unacceptable hazardous materials shipments
176.30 Dangerous cargo manifest
176.305 General stowage requirements
176.340 Combustible liquids in portable tanks
176.400 Stowage of Division 1.5, Class 4 (flammable solids) and Class 5 (oxidizers and organic peroxides) materials
176.410 Division 1.5 materials, ammonium nitrate and ammonium nitrate mixtures
176.415 Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers
176.5 Application to vessels
176.65 Alternative stowage procedures
176.69 General stowage requirements for hazardous materials
176.704 Requirements relating to transport indices and criticality safety indices
176.708 Segregation distances
176.76 Transport vehicles, freight containers, and portable tanks containing hazardous materials
176.80 Applicability
176.83 Segregation
176.84 Other requirements for stowage, cargo handling, and segregation for cargo vessels and passenger vessels
176.88 Applicability
176.89 Control of transport vehicles
176.90 Private automobiles
176.905 Vehicles having refrigerating or heating equipment
176.906 Stowage of engines and machinery
176.907 Polymeric Beads and Plastic Molding Compounds
177.800 Purpose and scope of this part and responsibility for compliance and training
177.802 Inspection
177.804 Compliance with Federal Motor Carrier Safety Regulations
177.810 Vehicular tunnels
177.816 Driver training
177.817 Shipping papers
177.817 Shipping papers
177.823 Movement of motor vehicles in emergency situations
177.834 General requirements
177.835 Class 1 materials
177.837 Class 3 materials
177.838 Class 4 (flammable solid) materials, Class 5 (oxidizing) materials, and Division 4.2 (self-heating and pyrophoric liquid) materials
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