There was the Kramatorsk radiological accident in the Soviet Union (Ukraine) where a cesium 137 source used at a gravel quarry was lost. Ended up in the wall of

There was the Kramatorsk radiological accident in the Soviet Union (Ukraine) where a cesium 137 source used at a gravel quarry was lost. Ended up in the wall of an apartment. Four people died of leukemia over 9 years.