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

Interpretation Response #19-0119

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

Interpretation Response Details

Response Publish Date:

Company Name: Nutrien

Individual Name: Clayton Droste

Location State: CO Country: US

View the Interpretation Document

Response text:

December 6, 2019

Mr. Clayton Droste
3005 Rocky Mountain Avenue
Loveland, CO  80534

Reference No. 19-0119

Dear Mr. Droste:

This letter is in response to your October 10, 2019, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171–180) applicable to the marking requirements for a Department of Transportation (DOT) Specification MC 331 cargo tank. Specifically, you provide a photograph illustrating the placement of inlet and outlet markings on an MC 331 cargo tank and ask whether it complies with § 178.337-9(c) of the HMR.

The answer is yes. In accordance with § 178.337-9(c), each cargo tank inlet and outlet, with the exception of gauging devices, thermometer wells, and pressure relief devices, must be marked "liquid" or "vapor" to designate whether it communicates with liquid or vapor when the cargo tank is filled to the maximum permitted filling density. Provided the marking is readily visible, legible, durable to withstand transport conditions, and clearly associated with the corresponding inlet/outlet, the marking would satisfy the requirements of the HMR. The marking(s) requirement may be satisfied using various locations and methods, including marking on the cargo tank shell.

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


T. Glenn Foster
Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division


Regulation Sections

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