In the case of Cobalt-60 the type of decay going on is Beta Decay. Which means the isotope is emitting an electron or positron. An example of the equation is shown below.
The half life of the cobalt-60 is 5.27 years which means that it will take approximately 10 half lives for 99% to decay. That’s about 50 years! So where do you run into cobalt-60 radiation? Don’t be frightened people are almost never exposed to cobalt 60. This radiation mainly occurs through radiation beams trying to sanitize in the food industry and through metals like ceramics and so forth. Most interaction with cobalt 60 comes from medical radiation or contaminated food and water. Although when ingested most cobalt 60 leaves through feces, some may be dissolved into tissue. Mainly with this isotope one is unlikely to run into threats unless undergoing a medical treatment. Once a threat has been detected however the person affected will undergo a series of treatments and tests to determine how much had been absorbed and what the best treatment from there will be. Radiation is the natural way an atom or isotope tries to stable and balance itself. With hundred of different isotopes radiation is everywhere so no one can really avoid it completely. Radiation can also be made artificially which is where x-rays and medical treatments come in. Since radiation is natural, like I said no one can 100% avoid it. The atoms nuclei are balancing and undergoing decay. Radiation has been around since the birth of the planet so there’s really nothing humans can do to prevent it.