System can filter extremely fine dust particles and aerosols, bringing pharmaceutical processing contamination levels down well below the most stringent OEL (Occupational Exposure Limit). The system features the exclusive use of sub-micron particulate filter cassettes in both the active filter and safety filter stages, affording the ability to accept high levels of contaminants in the inlet air stream; guaranteed 24-hour system operation; the ability to dedust different tablet presses with one filter system without product cross contamination; and integrated weighing systems to provide records of the quantities that have been extracted.