This study was intended to characterize commonly identified constituents of concern regarding airborne organic dust exposures in refuse-derived fuel (RDF) production facilities. Measurements were made of total and respirable particulates, total and respirable endotoxin, and total (viable plus non-viable) bioaerosols. Evaluation of particle size distribution was also made through sampling with an eight-stage personal cascade impactor. Sampling locations randomly chosen from a pool of locations frequented by plant personnel were rotated daily. The nature of the particulate at different stages of the RDF process was described through statistical comparisons. Electron microscopic examination of collected dust was conducted to observe particle morphology.