Interpretation Response #25-0056

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

Interpretation Response Details

Response Publish Date: 09/18/2025

Company Name: Commercial Vehicle Safety Alliance

Individual Name: Collin B. Mooney

Location State: DC Country: US

View the Interpretation Document

Response text:

September 18, 2025

Collin B. Mooney, MPA, CAE
Executive Director
Commercial Vehicle Safety Alliance
99 M Street, SE, Suite 1025
Washington, DC  20003

Reference No. 25-0056

Dear Mr. Mooney:

This letter is in response to your email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the marking requirements for nurse tanks. In your email, you state that § 173.315(m) allows for the use of a cargo tank, commonly known as a nurse tank, to transport anhydrous ammonia for agricultural purposes. You further state that § 173.315(m)(1)(vii) allows for the nurse tanks not to be marked or placarded on one end if that end contains valves, fittings, regulators or gauges when those appurtenances prevent the markings and placard from being properly placed and visible. You contend that there is confusion because § 172.328(b) states that "except for certain nurse tanks which must be marked as specified in § 173.315(m), each cargo tank transporting a Class 2 material subject to the HMR must be marked, in lettering no less than 50 mm (2.0 inches), on each side and each end with the proper shipping name or appropriate common name." Lastly, you state that the phrase, "except for certain nurse tanks" leads to confusion for enforcement personnel because it implies that certain nurse tanks require the proper shipping name or common name marking while others may not. You ask for clarification on whether this is the case.

The phrase "except for certain nurse tanks" refers to those nurse tanks meeting the singular exception provided for marking in § 173.315(m)(1)(vii)—those nurse tanks where valves, fittings, regulators or gauges prevent the markings and placard from being properly placed and visible on one end. In that case, the affected end need not be placarded or marked. Otherwise, all nurse tanks must be marked with the proper shipping name or common name on each side and each end as required by § 172.328(b).

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

Sincerely,

Alexander Wolcott
Acting Chief, Regulatory Review and Reinvention Branch
Standards and Rulemaking Division

§ 172.328(b), § 173.315(m), § 173.315(m)(1)(vii)

Regulation Sections