Uranium is both radioactive and a chemical toxin. Once inhaled or ingested, it can increase the risks of lung and bone cancer due to its alpha emissions. The decay products of uranium-238 pose additional health hazards. Polonium is distributed in soft tissues as well as bone. Radium is similar to calcium and accumulates on the surface of the bones and later in the matrix of bone structure.
Radium is dangerous when ingested.
It is a known agent of bone cancer as was discovered in the 1920s through the unfortunate fate of the radium dial painters who inadvertently ingested radium when licking the tips of their brushes to produce a fine point. Radon and its decay products are historically responsible for the elevated levels of lung cancer incurred by uranium miners. Conventional underground mining is most dangerous to workers because of higher exposure to radon decay products. The decay of these radionuclides in the lung has been the chief route of exposure of uranium miners and is historically responsible for the elevated levels of cancer they incur. Soluble uranium affects the kidneys if ingested or inhaled because of its chemical toxicity as a heavy metal.