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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 #21-0031

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

Interpretation Response Details

Response Publish Date:

Company Name: Mid State Tank Co., Inc.

Individual Name: Brian Kidd

Location State: IL Country: US

View the Interpretation Document

Response text:

June 10, 2021

Brian Kidd
Associate Engineer
Mid State Tank Co., Inc.
1357 Jonathan Creek Road
Sullivan, IL  61951

Reference No. 21-0031

Dear Mr. Kidd:

This letter is in response to your March 9, 2021, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to cargo tanks. Specifically, you ask about the use of Institute of Makers of Explosives Safety Library Publication No. 23 (IME Standard 23) for a non-DOT specification cargo tank transporting "UN3375, Ammonium nitrate gel, 5.1, II."

We have paraphrased and answered your questions as follows:

Q1. You ask whether a hazardous material that is classified as an oxidizer qualifies for use under IME Standard 23.

A1. The answer is yes. Ammonium nitrate emulsions, ammonium nitrate suspensions, or ammonium nitrate gels—classified as a Division 5.1 (Oxidizer) and that are precursor explosives—may be transported under the provisions of IME Standard 23.

Q2. You ask whether there are any tank design issues that would prevent the non-DOT specification cargo tank described in your email from qualification in accordance with IME Standard 23.

A2. This Office is unable to establish—within the scope of this request for an interpretation—whether there are any design elements that would preclude the packaging you described from the use of IME Standard 23. This determination should be made by the person certifying the packaging (e.g., design certifying engineer (DCE)) that it is compliant with IME Standard 23.

Q3. You ask whether the markings required on the nameplate in accordance with the IME Standard 23 may list the maximum allowable working pressure (MAWP) and the maximum design pressure as zero.

A3. Non-specification bulk packagings are required to be marked with the MAWP as certified by the DCE in accordance with IME SLP(F)(3)(d). Indicating that the determined MAWP and the maximum design pressure is zero is not specifically prohibited by IME Standard 23 and there may be instances in which marking either as zero is appropriate.

Q4. You ask which pressure testing procedure is required for the non-DOT specification cargo tank described in your email under IME Standard 23.

A4. Unless the non-DOT specification cargo tank in question is a sift-proof closed vehicle or a closed bulk bin, hydrostatic or pneumatic testing is required as specified in Appendix B, of IME Standard 23.

Q5. You ask what additional steps would be required to ensure this non-DOT specification cargo tank conforms to IME Standard 23.

A5. Non-DOT specification cargo tanks authorized for transport of certain explosives and oxidizers under § 173.66 of the HMR must be qualified, maintained, and repaired in accordance with the provisions set forth in IME Standard 23, specifically, Appendix B.  You should consult a DCE—per Section I Paragraph D of IME Standard 23—for additional conformance requirements. 

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


Regulation Sections

Section Subject
173.66 Requirements for bulk packagings of certain explosives and oxidizers