An expanded cohort study of 74,828 benzene-exposed and 35,805 unexpose
d workers were followed during 1972 to 1987, based on a previous study
in 12 cities in China. A small increase was observed in total cancer
mortality among benzene-exposed compared with unexposed workers (relat
ive risk [RR]=1.2). Statistically significant excesses were noted for
leukemia (RR=2.3), malignant lymphoma (RR=4.5), and lung cancer (RR=1.
4). When risks were evaluated by leukemia subtype, only acute myelogen
ous leukemia was significantly elevated (RR=3.1), although nonsignific
ant excesses were also noted for chronic myelogenous leukemia (RR=2.6)
and acute lymphocytic leukemia (RR=2.3). A significant excess was als
o found for aplastic anemia.