A variety of private and public sector programs are developing a new class of fire suppressants, known generically as solid particulate aerosols. These have superior volumetric efficiency, low initial and life-cycle costs, low toxicity, no known global atmospheric environmental impacts (ODP/GWP), and the potential for a wide variety of applications. Researchers are developing solid compound formulations that, when pyrotechnically initiated, generate powerful fire suppressant aerosols that behave more lightly than do air gases. Preliminary indications show that these aerosols are up to four times more powerful as fire suppressants on a mass basis than Halon 1301. Using a solid, gel, or powder as the starting point for generating an aerosol eliminates the need for piping and pressure cylinders and creates a potential for a wide variety of fire suppression applications in facilities, aircraft cargo containers, portable rapid deployment shelters, fuel storage tanks, battery/UPS rooms, unstaffed telecommunications facilities, and armored vehicle engine compartments. The speed of aerosol formation depends upon system design and configuration. This paper covers mechanisms of aerosol fire suppression and presents the most recent test results.