Tumors were induced in eastern oysters (Crassostrea virginica) by a mixture of aromatic hydrocarbons, an aromatic amine, polychlorinated biphenyls, chlorinated hydrocarbons, a nitrosoamine and heavy metals. Kidney and enteric tumors developed in oysters following exposure to a mixture containing 3,4-benzopyrene, 1,2-benzanthracene, 2-aminofluorene, N-nitrosodiethylamine, technical chlordane, Aroclors 1242 and 1254, p,p'-DDE, cadmium (CdCl2), chromium (K2CrO4) and lead (Pb(NO3)2). 2-Aminofluorene and N-nitrosodiethylamine, not measured in Black Rock Harbor sediment, were both added at 0.6 and 6.0 micrograms/g dry sediment. A 3% prevalence of low-grade renal and gastrointestinal tumors developed after 30 days in oysters fed water-column suspended sediment particulate spiked with the mixture of chemicals. Disease progression was most advanced in enteric adenomas. Both types are comparable to those produced after 30 days in the same organs by chemically contaminated Black Rock Harbor sediment.