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.

The latest general information on the Coronavirus (COVID-19) is available on Coronavirus.gov. For PHMSA contact information during the COVID-19 health emergency, please visit our page.

United States Department of Transportation United States Department of Transportation

PHMSA Safety Advisory Notice: Special Permits for Composite Gas Cylinders

Tuesday, January 12, 2021

On March 3, 2020, the Pipeline and Hazardous Materials Safety Administration (PHMSA) conducted an Investigative Hearing in response to incidents and roll-over crashes associated with operations using packagings authorized under certain Hazardous Materials Special Permits for the manufacture, mark, sale and use of non-DOT specification fully wrapped fiber reinforced composite gas cylinders.  The gas cylinders are used for the transportation of compressed natural gas (CNG) and other hazardous materials.  

As a result of the information presented at the hearing and subsequent evaluation, PHMSA is publishing this Safety Advisory Notice with recommendations to help facilitate the safe transportation of CNG under the terms of each related special permit.  See the Safety Advisory Notice in the related documents section for more details.