How do we become contaminated by radioactive isotopes?

According to the CDC, radiation exposure can happen when radioactive materials are released into the environment. 

Radiation exposure can occur during a nuclear power plant disaster, like during the infamous 3 Mile Island incident. It can happen during an atomic blast from a nuclear bomb, such was the case with Hiroshima and Nagasaki. 

It can occur when nuclear warheads are detonated.  

It can happen where radioactive materials are released from nuclear medical devices, like the nuclear medical equipment that is used to treat cancer.  

It can happen in facilities that use irradiation as a means of sterilizing medical equipment.  

It can happen at facilities that use industrial technology of a military nature, such is the case with weapons manufacturing and military research facilities. 

It can happen on your local university campuses where the students and faculty are conducting experimental research on biological organisms.  

It can happen when accidents occur during the shipment of nuclear waste on our nation’s highways and railroads. 

It has definitely happened when nuclear weapons testing released radioactive particles into the atmosphere which are then blown around the earth carried by high level winds and ultimately landing somewhere where no one has to take responsibility for it because radiation can’t be detected with your 5 senses. 

It has definitely happened in the case of nuclear bomb testing out in Nevada where it harmed the populations downwind.  

It can happen when dirty bombs are detonated and people come into contact with the radioactive particles that are released following the blast.

It can happen at industrial facilities that use radioactive waste to expose food and beverage containers, like Vindicators in Mulberry, Florida which exposes the containers to radioactive waste in order to "sterilize" the containers.

It can occur in industrial facilities that irradiate food for the purposes of shelf life extension. These facilities lease radioactive waste from the Department of Energy and then use it to irradiate food and spices (more on this later).