My employer was the prime contractor for the Texas emergency response in 2006 mentioned in your article. I was the radiation safety officer for the response.The weight of the Cs-137 contaminated steel was not quite 500,000 pounds as you wrote. Actually, it was very close [to] zero pound (or 0 kilogram, if you prefer).
Ooops! Shucky-dern. Panic FAIL.
Here's the thing: you're exposed to low levels of radioactivity all the frikkin' time. Your ancestors were exposed to even more. If you dig up the exposure vs. mortality curves (from some sources), they do mostly show the more-is-worse slope you'd expect -- except there's a little "hook" down at the low end, where more is better.*
Yeah, that's right. Better. If you were to achieve the wondrous realm of zero exposure, it just might make you a bit less healthy. (We're talkin' pretty low-level effects, data hard to dig out of the "noise.")
As a rule, yeah, please don't make cheese graters and bedframes with that hint of "hot" cobalt or pinch of plutonium; but don't lay awake of nights over it. Your odds of being hit by a bus are a lot higher. Your odds of comin' down with somethin' awful are far higher -- and greatly reduced by hand-washing, good hygiene and avoiding cheap tattoos.
* Natch-o, I cannot find the graph in question at present; I will check my sources and update. H'mm. Seems to still be fought over. Read for yourself.