In the dark recesses of the lower basement in ENS at the University of Texas at Austin, there was once a proton beam. The basement is only subterranean on one side of the building, and at ground level the other. There's a parking lot on this side of the building. The proton beam was aimed at a target, which was facing the parking lot. The shielding that the walls provided was proved to be inadequate. They know this because it screwed up a few car's paint jobs. This was all in the late 50's or early 60's. I can't imagine a guy telling his insurance agent in that era, "Uhh. the Power of the Atom screwed my paint job. Pay up." They piled an additional three feet of bricks on that side of the building. The proton beam is gone. The radiation remains.