Fathead minnows Pimephales promelas were exposed to phenanthrene adsorbed to <125 micrometers coal particles in a 14-day flow-through exposure to determine changes in histology and bioaccumulation. Based on light microscopic examination, coal particulates caused no obvious damage to external surfaces such as gills or skin and particulates were not observed to have accumulated in internal tissues. However, coal particles were readily ingested and this was followed by extensive mucous secretion by the gut mucosa. In addition, electron micrographs of the gut showed mucous globules in coal-exposed epithelium but no erosion of microvilli. Phenanthrene bioaccumulation was compared in fish exposed to dissolved aqueous phenanthrene and fish exposed to dissolved aqueous phenanthrene plus coal particulate-bound phenanthrene. Enhanced phenanthrene uptake was not measured in coal-exposed fish and bioconcentration factors were 1,000 - 4,000 during the 14-day exposure period. Elimination of coal from the gut and phenanthrene from the tissues was rapid; both were undetectable after a 24-hour depuration period.