USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #23-0082

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

Interpretation Response Details

Response Publish Date:

Company Name: The University of Alabama at Birmingham

Individual Name: Justin Roth

Location State: AL Country: US

View the Interpretation Document

Response text:

December 5, 2023

Justin Roth
Senior Biosafety Officer
The University of Alabama at Birmingham
933 19th St. S. CH19 412P
Birmingham, AL  35294

Reference No. 23-0082

Dear Mr. Roth:

This letter is in response to your August 22, 2023, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the disposal of an animal carcass (i.e., a mouse carcass) engrafted with human tissues and then infected with the human immunodeficiency virus (HIV) for therapy research. Specifically, you ask whether a mouse carcass used as a model to study HIV infection/viremia would be considered "a culture" and whether such animal carcasses must be classified as Category A waste.

The answer is no. "Culture" is defined in § 173.134(a)(3) to mean an infectious substance containing a pathogen that is intentionally propagated. This typically refers to pathogens cultivated in a growth medium. It is the opinion of this office that "culture" does not include animals infected with a pathogen.

A material is not a Category A infectious substance if it is not in a form generally capable of causing permanent disability or life-threatening or fatal disease in otherwise healthy humans or animals when exposure to it occurs and may appropriately be classified as a Category B infectious substance under §173.134(a)(1)(i). Category B wastes derived from biomedical research, which includes the production and testing of biological products and, in this instance, these animal carcasses, would be considered "Regulated medical waste or clinical waste or (bio) medical waste" and must be transported in accordance with § 173.197.

Note that ultimately it would be the offeror's responsibility to evaluate and properly classify a hazardous material using the criteria specified for Category A or Category B infectious substances (waste) found in § 173.134.

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

173.134, 173.134(a)(1)(i), 173.134(a)(3), 173.197

Regulation Sections

Section Subject
173.134 Class 6, Division 6.2-Definitions and exceptions
173.197 Regulated medical waste