We found some intereting articles about this topic for example we know about the chernobly disaster:

             Impact of the Chernobyl accident

"The accident caused the largest uncontrolled radioactive release into the environment ever recorded for any civilian operation, and large quantities of radioactive substances were released into the air for about 10 days. This caused serious social and economic disruption for large populations in Belarus, Russia and Ukraine. Two radionuclides,were particularly significant for the radiation dose they delivered to members of the public."

This is a summary because the topic is very long if you whant read more about it you can go to this link:http://www.world-nuclear.org/info/Safety-and-Security/Safety-of-Plants/Chernobyl-Accident/