There was another incident 25-odd years ago near where I grew up on the US/Mexico border. Radioactive steel (with cesium or cobalt, from medical equipment, IIRC) was sold for scrap and turned into various things like restaurant tables. It was only discovered when a geiger counter was turned on by a bored geologist waiting for food.
Surprisingly it's hard to track down. The Wiki article linked abode has one or two mentions of a "Mexico incident", but that's it. Here are some others:
