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.

Site Notification

Site Notification

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Notice and Request for Comments: FAQs - Applicability of the Hazardous Materials Regulations

PHMSA is conducting an initiative to convert historical letters of interpretation applicable to the Hazardous Materials Regulations that have been issued to specific stakeholders into broadly applicable frequently asked questions (FAQs) on its website. By creating a repository of FAQs, PHMSA seeks to eliminate the need for recurring requests for common letters of interpretations. Interested persons are invited to submit comments on the initiative and input on the prioritization of future sets of FAQs on or before May 23, 2022. 

See the Federal Register Notice for more details, which introduces the initiative and its objectives to those subject to the Hazardous Materials Regulations.

DOT is committed to ensuring that information is available in appropriate alternative formats to meet the requirements of persons who have a disability. If you require an alternative version of files provided on this page, please contact
Effective Date: Tuesday, March 22, 2022
Issued Date: Tuesday, March 22, 2022