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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 175 on the ECFR website

Interpretation Responses

Ref ID Date Company Name Individual Name Response Document
20-0041 Tatonduk Outfitters Limited, dba Everts Air Cargo Robert Ragar View

Regulation Sections

Section Subject
175.1 Purpose, scope and applicability
175.3 Unacceptable hazardous materials shipments
175.8 Exceptions for operator equipment and items of replacement
175.9 Special aircraft operations
175.10 Exceptions for passengers, crewmembers, and air operators
175.20 Compliance and training
175.25 Passenger notification system
175.26 Notification at cargo facilities of hazardous materials requirements
175.30 Inspecting shipments
175.31 Reports of discrepancies
175.33 Shipping paper and notification of pilot-in-command
175.34 Exceptions for cylinders of compressed oxygen or other oxidizing gases transported within the State of Alaska
175.75 Quantity limitations and cargo location
175.78 Stowage compatibility of cargo
175.88 Inspection, orientation and securing packages of hazardous materials
175.90 Damaged shipments
175.310 Transportation of flammable liquid fuel; aircraft only means of transportation
175.501 Special requirements for oxidizers and compressed oxygen
175.630 Special requirements for Division 6.1 (poisonous) material and Division 6.2 (infectious substances)materials
175.700 Special limitations and requirements for Class 7 materials
175.701 Separation distance requirements for packages containing Class 7 (radioactive) materials in passenger-carrying aircraft
175.702 Separation distance requirements for packages containing Class 7 (radioactive) materials in cargo aircraft
175.703 Other special requirements for the acceptance and carriage of packages containing Class 7 materials
175.704 Plutonium shipments
175.705 Radioactive contamination
175.706 Separation distances for undeveloped film from packages containing Class 7 (radioactive) materials
175.900 Handling requirements for carbon dioxide, solid (dry ice)