The report summarizes EPA's inhouse research program in fabric filtration, involving investigations into the basic mechanisms of dust/fabric interaction in order to develop improved understanding of the process. Evaluation of new fabrics in laboratory tests that can be extrapolated to field applications is a second major goal of the inhouse research. Among the fabrics evaluated were a spunbonded nylon (Cerex), a spunbonded polyester (Reemay), and expanded polytetrafluorethylene (PTFE) laminate (Gore Tex/Nomex), and various specially developed fabrics, including uncalendared needled felts and coated fibrous glasses. These fabrics all performed well or exhibited some desirable property. Other fabrics, less attractive for particulate control, were tested less completely. Development of a mathematical model capable of predicting fabric filtration performance was attempted. The complexities of this task led to breaking the overall process into simpler subdivisions for study, including: particle penetration mechanisms, temperature and age effects, bag cleaning techniques, and electrostatic effects.