The health issues related to uranium are primarily related to its chemical toxicity, not it's weak alpha emissions. Inhalation/ingestion of uranium dust is certainly a radiological concern, but not nearly as concerning as radium, radon, iodine-131, cobalt-60 or any of the short lived isotopes used in medicine or industry. A speck of radium salt large enough to see is more of a radiological health risk than a kilogram of uranium oxide (yellow cake). For purposes unrelated to firearms, I keep tens of grams of uranium oxides and metal in my home and it is perfectly safe (and legal for everyone under a general NRC license). It would NOT be safe to keep ANY visible amount of the other materials mentioned except as a specially prepared sealed source. As far as cobalt-60, any significant quantity would be stored in a container shielded with -- you guessed it -- uranium. As far as the chemical toxicity of uranium, it's in the same ballpark as many of the heavy metals such as lead. Anyone who has been outside, especially in a part of the world where radon inside homes is a concern, has inhaled lots of dust containing mixed uranium oxides.