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Interpretation Response #21-0051

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

Interpretation Response Details

Response Publish Date:

Company Name: Railsback Hazmat Safety Professionals, LLC

Individual Name: Rex Railsback

Location State: KS Country: US

View the Interpretation Document

Response text:

September 13, 2021

Mr. Rex Railsback
Railsback Hazmat Safety Professionals, LLC
312 Lawrence Avenue
Lawrence, KS  66049

Reference No. 21-0051

Dear Mr. Railsback:

This letter is in response to your May 10, 2021, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to nurse tanks.

We have paraphrased and answered your questions as follows:

Q1. You ask whether a nurse tank meeting the requirements of § 173.315(m) is subject to the emergency control requirements found in § 173.315(n).

A1. The answer is no. The standalone requirements of paragraph (m) allows for the use of a cargo tank commonly known as "nurse tank" when operated by a private motor carrier as an implement of husbandry transporting anhydrous ammonia exclusively for agricultural purposes to be excepted from Part 178- Specification Packages, but must meet requirements of § 173.315(m)(1)(i) through (vii) to be qualified and defined as a nurse tank.

Q2. You ask whether the nurse tank requirements in § 173.315(m) are standalone provisions or if nurse tanks are subject to other requirements in § 173.315.

A2. See answer A1.

Q3. You ask will a nurse tank also meet the definition of a cargo tank motor vehicle and/or a motor vehicle per § 171.8 since a nurse tank, per § 173.315(m), is a cargo tank.

A3. The answer is no. A nurse tank would not meet the definition of a cargo tank motor vehicle and/ or motor vehicle in accordance with either definition in § 171.8.

Q4. You ask whether two nurse tanks mounted side-by-side on a farm wagon, with only three inches of clearance between the inboard sides of each tank and not visible during transportation, would require the non-visible inboard sides of each cargo tank to also have placards and markings if the farm wagon is properly placarded and marked on each outboard side and each end.

A4. The answer is yes. PHMSA's Letter of Interpretation (Ref. No. 10-0120), specifically, answers this question.

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


Dirk Der Kinderen
Chief, Standards Development Branch
Standards and Rulemaking Division

171.8, 173.315, 173.315(m), 173.315(n), 173.315(m)(1)(i)-(vii)

Regulation Sections

Section Subject
171.8 Definitions and abbreviations
173.315 Compressed gases in cargo tanks and portable tanks