Radiation of 3 different type from uranium and it's decay products. Natural decay and fissioning of uranium produce these effects. Has the greatest penetrating power of the three types. Humans must be shielded from it by lead or a thick concrete barrier. Exposure to gamma radiation can damage organs in the body.
Most fission products emit both gamma and beta radiation.
Beta radiation causes the most damage if its particles are ingested or inhaled, or if the radioactive materials come in contact with skin. Tritium and strontium-90, which seeks the bones in the human body, emit beta radiation. It can be blocked by a sheet of paper and cannot penetrate or burn intact human skin. But it is harmful if swallowed or inhaled. Plutonium emits alpha radiation, which is why it is dangerous if inhaled or ingested.