The Bureau of Industry and Security (BIS) has identified four naturally occurring, dual-use, biological toxins for evaluation as a potential emerging technology, consistent with the interagency process described in Section 1758 of the Export Control Reform Act of 2018 (ECRA) (50 U.S.C. 4801-4852), as codified under 50 U.S.C. 4817.  These toxins have the potential (through either accidental or deliberate release) to cause casualties in humans or animals, degrade equipment, or damage crops or the environment.  Furthermore, they are now capable of being more easily isolated and purified due to novel synthesis methods and equipment.  Consequently, the absence of export controls on these toxins could be exploited for biological weapons purposes.  To address this concern, BIS proposes to amend the Commerce Control List (CCL) by adding these toxins to Export Control Classification Number (ECCN) 1C351.  This rule requests public comments to ensure that the scope of these proposed controls will be effective and appropriate (with respect to their potential impact on legitimate commercial or scientific applications).