Exposures to organic solvents (including benzene), ionizing radiation and low frequency electromagnetic fields have been suggested as risk factors for leukemias in adults. Exposure to herbicides of the phenoxyacid variety (2, 4, 5-T; 2, 4-D) has been reported to be associated with an increased risk of non-Hodgkin's lymphomas. In addition several studies have suggested that agricultural workers have an excess risk of hematolymphopoietic malignancies, although no specific agent has yet been identified. Italy is particularly attractive for investigating further these associations, because: a) there is a high prevalence of exposure to solvents in industrial areas (estimated to be 10-16% in the province of Torino, Varese and Florence), and a high prevalence of exposure to herbicides (including phenoxyacides) in agricultural areas; b) there is also considerable extra-occupational exposure to solvents and pesticides; c) competent groups of hematologists exist in several towns, using advanced diagnostic techniques including cytogenetics. We propose therefore to conduct a multicenter population-based case-control study in 11 italian areas, chosen on the basis of a high exposure prevalence. In three years, we intend to interview approximately 1100 cases of leukemia, 1900 cases of lymphoma (Hodgkin and non-Hodgkin) and 400 cases of myeloma; 1900 randomly selected individuals, residents of the same areas, will serve as a population control group. Cases will be all those occurring in the study period among residents of the 11 areas, newly diagnosed. Particular care will be dedicated to diagnostic aspects, including B- and T- cell characterization. Cases and controls will be blindly interviewed by trained personnel.(ABSTRACT TRUNCATED AT 250 WORDS)