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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
105.40 Designated agents for non-residents
105.5 Definitions
106.100 Required information for a petition for rulemaking
106.105 PHMSA response to a petition for rulemaking
106.130 PHMSA response to an appeal
106.95 Requesting a change to the regulations
107.1 Definitions
107.105 Application for special permit
107.107 Application for party status
107.109 Application for renewal
107.201 Purpose and scope
107.202 Standards for determining preemption
107.203 Application
107.205 Notice
107.211 Petition for reconsideration
107.305 Investigations
107.307 General
107.333 Criminal penalties generally
107.401 Purpose and scope
107.402 Application for designation as a certification agency
107.501 Scope
107.502 General registration requirements
107.504 Period of registration, updates, and record retention
107.601 Applicability
107.606 Exceptions
107.608 General registration requirements
107.705 Registrations, reports, and applications for approval
107.709 Processing of an application for approval, including an application for renewal or modification
107.713 Approval modification, suspension or termination
107.801 Purpose and scope
107.805 Approval of cylinder and pressure receptacle requalifiers
130.5 Definitions
171.1 Applicability of Hazardous Materials Regulations (HMR) to persons and functions
171.10 Units of measure
171.12 North American Shipments
171.15 Immediate notice of certain hazardous materials incidents
171.16 Detailed hazardous materials incident reports
171.2 General requirements
171.22 Authorization and conditions for the use of international standards and regulations
171.23 Requirements for specific materials and packagings transported under the ICAO Technical Instructions, IMDG Code, Transport Canada TDG Regulations, or the IAEA Regulations
171.24 Additional requirements for the use of the ICAO Technical Instructions
171.25 Additional requirements for the use of the IMDG Code
171.25 Additional requirements for the use of the IMDG Code
171.26 Additional requirements for the use of the IAEA Regulations
171.3 Hazardous waste
171.4 Marine pollutants
171.6 Control numbers under the Paperwork Reduction Act
171.7 Reference material