The lung cancer mortality rate in Xuan Wei County, China is among the highest in the country and has been associated with exposure to indoor smoky coal emissions that contain high levels of polycyclic aromatic hydro carbons. In a case-control study, it was found that the individual susceptibility to lung cancer risk may be increased by GSTM1 null genotype as well as overexpression of the p53 protein. It is likely that the lung cancer excess in Xuan Wei County results from the complex interaction of genetic and environmental factors that will require further research to be understood.