Technologies Underlying Weapons of Mass Destruction/Office of Technology Assessment

In 1993 the US Government knew that silicon was used to enhance dispersal of powdered microbial agents and toxins.  OTA produced some very useful research, but the agency no longer exists.

U.S. Congress, Office of Technology Assessment, Technologies Underlying Weapons of Mass Destruction, OTA-BP-ISC-115 (Washington, DC: U.S. Government Printing Office, December 1993).

CHEMICAL ADDITIVES
The stability of a microbial aerosol can be
increased by adding a variety of compounds to the
spray material.58 Moreover, antiagglomerants such
as colloidal silica help prevent the clumping of
freeze-dried microbial agents and toxins that have
been milled into a fine powder.