Interpretation Response #25-0044
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: Centers for Disease Control and Prevention
Individual Name: Keri Kolb
Location State: CO Country: US
View the Interpretation Document
Response text:
August 7, 2025
Keri Kolb
Centers for Disease Control and Prevention
3156 Rampart Road
Mail Stop 2
Fort Collins, CO 80521
Reference No. 25-0044
Dear Ms. Kolb:
This letter is in response to your April 10, 2025 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to materials classified and described by the International Civil Air Organization (ICAO) as Division 6.2 infectious substances. Specifically, you request clarification on the proper classification (i.e., Category A or B) of chimeric viruses (non-culture). In your incoming email, you reference the indicative list provided in the ICAO Technical Instructions for the Safe Transport of Dangerous Goods by Air (ICAO Technical Instructions) and the International Air Transportation Association Dangerous Goods Regulations.
PHMSA notes that the Categories A and B described in the HMR at § 173.134 do not incorporate by reference nor are they intended to mirror the Categories A and B for Division 6.2 infectious substances listed in the ICAO Technical Instructions. For purposes of transporting infectious substances within the United States, the indicative list of example Category A infectious substances contained in the ICAO Technical Instructions should be considered solely as informational guidance to assist in appropriately classifying Category A and B infectious substances commensurate with the relevant HMR criteria. The ICAO list is not exhaustive and may omit new or emerging pathogens and require amendments from time to time based on the latest available data. Therefore, the indicative ICAO list is not included in the HMR as it is not intended to be regulatory in nature.
Furthermore, for purposes of the HMR, it is the shipper's responsibility to properly classify the material in accordance with § 173.134 classification criteria for Division 6.2 infectious substances. Therefore, chimeric viruses, whether in a culture or non-cultured form, must be classified in accordance with the criteria in § 173.134 and assigned the appropriate category for transportation.
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk DerKinderen
Chief, Standards and Development Branch
Standards and Rulemaking Division
§ 173.134
Regulation Sections
| Section | Subject |
|---|---|
| 173.134 | Class 6, Division 6.2-Definitions and exceptions |