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.

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

Interpretation Response #17-0040

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: HazMat Resources, Inc.

Individual Name: Danny Shelton

Location State: TN Country: US

View the Interpretation Document

Response text:

Mr. Danny Shelton
124 Rainbow Drive, Suite 2471
Kingsport, TN 37663

Reference No. 17-0040

Dear Mr. Shelton:

This letter is in response to your April 25, 2017, letter requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to marking cargo tank inlets and outlets to indicate whether they communicate with liquid or vapor when the cargo tank is filled to the maximum permitted filling density. You reference a previously-issued letter of interpretation, stating that the guidance therein is too limiting and does not account for the overall intent of the marking requirement. You believe that the intent of § 178.337-9(c) is fulfilled as long as the inlets and outlets are marked so that one can determine whether the inlet or outlet communicates with a liquid or vapor—whether that marking be on the cargo tank wall, accident protection frame, or the outlets themselves.

Your understanding is correct. Provided the marking is readily visible, legible, durable to withstand transport conditions, and clearly associated with the corresponding inlet or outlet, marking in the locations you describe would satisfy the requirements of the HMR.

I hope this information is helpful. Please contact us if we can be of further assistance.


Shane Kelley
Standards and Rulemaking Division

Regulation Sections

Section Subject
178.337-9 Pressure relief devices, piping, valves, hoses, and fittings