The article details work from an epidemiological survey on lung cancer was conducted in 1117 coking plant workers and 350 gas plant workers of Taiyuan Iron & Steel Co., China, and 490,000 residents in the local coking workshops sites. The mortality rate of lung cancer in the surveyed sample was substantially higher than average. The emission of large amounts of oncogenic polycyclic hydrocarbons causing environmental pollution, the old installation and primitive coking method, and the lack of personal protection were the reasons for such high lung cancer mortality. A preventive measure with selenium and sand pear mixture was tested in experimental animal models, displaying promising results.