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Below are the available interpretations and guidance for the given section. To return to the list of parts, use the Parts link above. If you do not see any guidance or interpretation information below, that means there is none available for the given part/section. Return to the search page to browse additional regulations sections.

PHMSA has published several Frequently Asked Questions (FAQ) documents on regulatory topics. Please review our FAQ documents below:

Additionally PHMSA has Hazardous Materials FAQs based on letters of interpretation on the following topics:

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 regulations text of the section can be found on the eCFR website. To view the regulations text, use the link below. For assistance, please send an email to

View part 180 on the ECFR website

Interpretation Responses

Ref ID Date Company Name Individual Name Response Document
23-0003 Denver Fire Department Chris Bartlett View
16-0099 Veolia North America Jennifer Eberle View

Regulation Sections

Section Subject
180.1 Purpose and scope
180.2 Applicability
180.3 General requirements
180.201 Applicability
180.203 Definitions
180.205 General requirements for requalification of specification cylinders
180.207 Requirements for requalification of UN pressure receptacles
180.209 Requirements for requalification of specification cylinders
180.211 Repair, rebuilding and reheat treatment of DOT-4 series specification cylinders
180.212 Repair of seamless DOT 3-series specification cylinders and seamless UN pressure receptacles
180.213 Requalification markings
180.215 Reporting and record retention requirements
180.217 Requalification requirements for MEGCs
180.350 Applicability and definitions
180.351 Qualification of IBCs
180.352 Requirements for retest and inspection of IBCs
180.401 Applicability
180.403 Definitions
180.405 Qualification of cargo tanks
180.407 Requirements for test and inspection of specification cargo tanks
180.409 Minimum qualifications for inspectors and testers
180.411 Acceptable results of tests and inspections
180.413 Repair, modification, stretching, rebarrelling, or mounting of specification cargo tanks
180.415 Test and inspection markings
180.416 Discharge system inspection and maintenance program for cargo tanks transporting liquefied compressed gases
180.417 Reporting and record retention requirements
180.501 Applicability
180.503 Definitions
180.505 Quality assurance program
180.507 Qualification of tank cars
180.509 Requirements for inspection and test of specification tank cars
180.511 Acceptable results of inspections and tests
180.513 Repairs, alterations, conversions, and modifications
180.515 Markings
180.517 Reporting and record retention requirements
180.519 Periodic retest and inspection of tank cars other than single-unit tank car tanks
180.601 Applicability
180.603 Qualification of portable tanks
180.605 Requirements for periodic testing, inspection and repair of portable tanks