On 22 July, a truck containing 10 lead-lined boxes was intercepted at the Bulgarian-Romanian border, after Bulgarian scanning detectors measured radiation 200 times the normal background radiation. The consignment, destined for Iran, was discovered by the Bulgarian Nuclear Regulatory Agency (NPA) to contain soil-measuring devices incorporating the radioisotopes cesium-137 and americium-beryllium. In the light of the continuing controversy over Iran's record of nondisclosure about its nuclear activities, questions arise as to the intended purpose of such a consignment. The acquisition of such a cargo would allow its end users to construct, or experiment with, radiological weapons. The radioisotopes inside the...