Narong Penanam was arrested in Thailand today trying to sell a container of Cesium-137. That is one of the materials desired for the making of the so called "dirty bombs". Cesium 137 is used in industry and medicine, often in gauges. A dirty bomb, or radiological dispersion bomb, is a conventional bomb combined with radioactive materials. When the bomb explodes, the radioactive material is propelled outward. Imagine, for example, the van that blew up the Federal Building in Oklahoma City also containing large amounts of radioactive material that is then spread over the city. Kudos to the investigators from the United States who found out about this and tipped the Thai authorities. The battle rages on, but obviously our side is doing a good job.