When a water purifier was replaced, air entered the system. Safety equipment failed to notice the foreign substance in the system because the equipment did not work correctly and the operators made mistakes. The air that
had been accidentally introduced was ultimately responsible for the accident.
The results of the accident created many problems. Radioactive water entered the Susquehanna River and radioactive steam poisoned the atmosphere.
The reactor's cooling system was filled with a large amount of hydrogen gas. Some people immediately feared that the reactor core would melt.
The public reaction was swift. Many people wanted to evacuate the area out
of fear that they would be exposed to deadly radioactive poisoning. Industry and government tried to reduce fears, often giving out false information to accomplish that goal.
The Kemeny Commission, which investigated the accident, blamed the nuclear industry and the Nuclear Regulatory Commission for failing to have proper regard for nuclear safety, and said that workers should receive better training. The Commission also criticized the response of the government and plant
No one died in the accident, but some local people may be hurt by exposure to radiation. Cleaning up the plant cost over US $1 billion and took more than six years.