The relationship between worker exposure to benzene (71432) contaminated toluene (108883) and the development of bone marrow disease was examined in a case study. The exposures experienced by two workers of the printing industry, one with chronic myelogenous leukemia (CML) and one with thrombocytopenia, were investigated retrospectively. Exposure estimation was based on employee interviews and workplace documents. The workers were employed by the same company for over 25 years, both working mainly in batch preparation. At the coating machines, workers were often exposed through inhalation and skin absorption to toluene, benzene, methylethylketone (78933) (MEK), and alcohols. In the mixing room, workers were routinely exposed to toluene, benzene, and MEK. The workers also indicated that skin cuts sustained at work were commonly rinsed with MEK and toluene, and toluene was used to clean coatings from the hands. A literature review was conducted in order to better estimate worker exposures. Research was cited which indicated that until the 1980s, toluene was frequently contaminated with up to 25% benzene. Other studies related benzene exposure to the development of CML and thrombocytopenia. The author concludes that the findings implicate workplace exposures, including exposure to benzene, in the development of the workers' diseases. Retrospective exposure profiles based on employee interviews can successfully identify incidences of occupational disease.