Select Agents and Toxins Exclusions

The select agent regulations (7 CFR Part 331, 9 CFR Part 121, and 42 CFR Part 73) established a procedure by which an attenuated strain of a select biological agent or toxin that does not pose a severe threat to public health and safety, animal health, or animal products may be excluded from the requirements of the select agent regulations.

Excluded Strains of HHS and USDA Select Agents and Toxins

Based upon consultations with subject matter experts and a review of relevant published studies and information provided by the entities requesting the exclusions, the Federal Select Agent Program has determined that the following attenuated select agent strains or less toxic select toxins are not subject to the requirements of the select agent regulations.

An excluded select agent strain or modified toxin will be subject to the regulations if there is a reintroduction of factor(s) associated with virulence, toxic activity, or other manipulations that modify the attenuation such that virulence or toxic activity is restored or enhanced. In addition, excluded select agent strains or modified toxins are not exempt from the requirements of other applicable regulations or guidelines (e.g., NIH guidelines, USDA/APHIS permits, etc.).

Nontoxic HHS toxins, Section 73.3 (d)(2)


Excluded Toxins Modified to be Less Potent or Toxic, Section 73.3 (e)


Excluded Attenuated Strains of HHS Select Agents, Section 73.3 (e)


Excluded Attenuated Strains of Overlap Select Agents, Section 73.4 (e) and 121.4 (e)


Attenuated Strains of USDA-only select agents excluded, Section 121.3 (e)