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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 #23-0058

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

Interpretation Response Details

Response Publish Date:

Company Name: Carbochem Inc,

Individual Name: Mr. Gavin Kahn

Location State: PA Country: US

View the Interpretation Document

Response text:

November 30, 2023

Mr. Gavin Kahn
Carbochem Inc,
308 East Lancaster Ave
Wynnewood, PA 19096

Reference No. 23-0058

Dear Mr. Kahn:

This letter is in response to your June 28, 2023, email pertaining to activated carbon transported in accordance with the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180). In your email, you note that chemically activated carbon is frequently shipped as a Division 4.2 (Spontaneously Combustible Material) material due to its self-heating properties. To determine the classification of your product, you state that you arrange for your Carbochem® activated carbon grades to be tested using United Nations (UN) Test N.4 "Test method for self-heating substances," in accordance with Section of the UN Manual of Test and Criteria (UNMTC).  You state that the results of the testing—as provided in your email—indicate that Carbochem® DC-50 (steam activated) exhibits no self-heating; while Carbochem® CA-50 (chemically activated) shows some self-heating, but not at 140 °C for a 25mm cube sample.  You request confirmation that your test results accurately determine that your Carbochem products should not be classified as Division 4.2 hazardous materials.

In accordance with § 173.22 of the HMR, it is the shipper's responsibility to properly classify a hazardous material. This Office generally does not perform this function. However, based on the test data and certification you provided, we agree that your company's products—as described in your email—do not meet the definition of a Division 4.2 hazardous material. In addition, please note that if your products do not meet any other hazard class as defined in part 173 of the HMR, and are not a hazardous substance, hazardous waste, or marine pollutant, they are not subject to the HMR.

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

173, 173.22

Regulation Sections

Section Subject
173.22 Shipper's responsibility