Benzene has long been recognized as capable of increasing the risk of
leukemia and other blood disorders, and US regulations mandate that occupational
exposure to this widely used industrial chemical should not exceed 1 ppm.
Now, a study of shoe factory workers in China by US and Chinese scientists
has found that benzene can damage blood-forming cells in the bone marrow even
at levels below this threshold, a finding that could prompt a reevaluation
of the 1-ppm workplace standard (Lan et al. Science . 2004;306:1774-1776).
Stephenson J. Benzene Caution. JAMA. 2005;293(3):286. doi:10.1001/jama.293.3.286-d