The National Cancer Institute (NCI) and the Chinese Academy of Preventive Medicine (CAPM), whose name was recently changed to the China Center for Disease Control (CDC) previously established a cohort of 75,000 workers exposed to benzene in 12 cities in China and 35,000 unexposed comparison workers, to investigate the relationship between benzene exposure and cancer risk, from 1972 to 1987. We followed up each worker using factory records and reported results suggesting that benzene exposure under 10 ppm may be associated with increased risk of acute non-lymphocytic cancer and could also be associated with increased risk of lymphoma and lung cancer. We have now laid the groundwork for a further epidemiologic investigation in China to evaluate health risks from lower levels of benzene exposure, particularly as present in the factories during the 1990s. The cohort was followed up through 1999, and through this effort we have identified 3260 subjects for study, including cases (HLD malignancies, n= 161; benzene poisoning, n= 1040; lung cancer, n= 560) and 1500 subjects in a cohort sub-sample to be used as the comparison group. In addition, we have identified a series of cases with benzene poisoning and controls from the same factories outside of the cohort (n = 600).