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 (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
171.8 Definitions and abbreviations
171.9 Rules of construction
172.101 Purpose and use of hazardous materials table
172.101 Purpose and use of hazardous materials table
172.102 Special provisions
172.102 Special provisions
172.200 Applicability
172.201 Preparation and retention of shipping papers
172.202 Description of hazardous material on shipping papers
172.203 Additional description requirements
172.204 Shipper's certification
172.205 Hazardous waste manifest
172.3 Applicability
172.300 Applicability
172.301 General marking requirements for non-bulk packagings
172.302 General marking requirements for bulk packagings.
172.303 Prohibited marking
172.304 Marking requirements
172.310 Class 7 (radioactive) materials
172.312 Liquid hazardous materials in non-bulk packagings
172.313 Poisonous hazardous materials
172.315 Limited quantities
172.316 Packagings containing materials classed as ORM-D
172.322 Marine pollutants
172.323 Infectious substances
172.324 Hazardous substances in non-bulk packagings
172.325 Elevated temperature materials
172.326 Portable tanks
172.327 Petroleum sour crude oil in bulk packaging
172.328 Cargo tanks
172.330 Tank cars and multi-unit tank car tanks
172.331 Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks
172.332 Identification number markings
172.334 Identification numbers; prohibited display
172.336 Identification numbers; special provisions
172.338 Replacement of identification numbers
172.400 General labeling requirements
172.400a Exceptions from labeling
172.401 Prohibited labeling
172.402 Additional labeling requirements
172.403 Class 7 (radioactive) material
172.405 Authorized label modifications
172.406 Placement of labels
172.407 Label specifications
172.411 EXPLOSIVE 1.1, 1.2, 1.3, 1.4, 1.5 and 1.6 labels, and EXPLOSIVE Subsidiary label
172.415 NON-FLAMMABLE GAS label
172.417 FLAMMABLE GAS label
172.419 FLAMMABLE LIQUID label
172.423 DANGEROUS WHEN WET label