happened on monday at a gas station in a town near mexico city. officials with the international atomic energy agency are reporting now that the truck was delivering a load of cobalt 60 from a hospital in tijuana to a storage center for radioactive waste. a sort of routine matter. the doctors say they use cobalt 60 to treat cancer, but the experts are saying in theory terrorists could potentially use it to make a so-called dirty bomb which uses conventional explosives to spread radiation. those same authorities say this image shows workers preparing to transport the shipment of cobalt 60. the u.n. warns that the substance would be extremely dangerous. and that s a quote, if someone were to damage it or remove it from the protective casing. casey ste gal live in our newsroom in dallas. who knows if the people who got the truck had any clue what was in the back of the truck. maybe they just wanted the truck. but now they have cobalt 60. how dangerous is it?