Interpretation Response #25-0108
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: DG Advisor
Individual Name: Ben Barrett
Location State: WY Country: US
View the Interpretation Document
Response text:
December 11, 2025
Ben Barrett
DG Advisor
6 Starry Way
P.O. BOX 248
Dubois, WY 82513
Reference No. 25-0108
Dear Mr. Barrett:
This letter is in response to your August 4, 2025 letter and previous conversations with PHMSA staff requesting clarification of the provisions of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the classification of a hazardous material. Your client has developed a new agricultural fertilizer compound consisting of 69.5 percent ammonium nitrate, 30.5 percent ammonium phosphate, and no combustible substances. It is your understanding that this mixture is not regulated as a hazardous material because in accordance with the flowchart in Section 39.5 of the United Nations (UN) Manual of Tests and Criteria—Section 39.5—titled "Classification criteria" (which is incorporated by reference in the HMR), analysis of the fertilizer's properties leads to box 26 which states it is "Not classified." You seek confirmation that the mixture as described is not regulated as a hazardous material.
In accordance with § 173.22 of the HMR, it is the shipper's responsibility to properly classify a hazardous material, as this Office does not generally perform this function. However, based on the information provided in your letter, it is the opinion of this Office that the agricultural fertilizer you have described is not regulated as a hazardous material. This is based on our understanding that the company classified its material in accordance with § 172.102, special provision 132, and followed the decision logic and required testing in the UN Manual of Tests and Criteria, 7th revised edition, as described in your incoming letter.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk DerKinderen
Chief, Standards Development Branch
Standards and Rulemaking Division
§ 172.102, § 173.22
Regulation Sections
| Section | Subject |
|---|---|
| 172.102 | Special provisions |
| 173.22 | Shipper's responsibility |