On March 28, 1979, equipment failures and operator error contributed to loss of coolant and a partial core meltdown at the Three Mile Island Nuclear Power Plant in Pennsylvania. The World Nuclear Association has stated that cleanup of the damaged nuclear reactor system at TMI-2 took nearly 12 years and cost approximately US $973 million. Benjamin K. Sovacool, in his 2007 preliminary assessment of major energy accidents, estimated that the TMI accident caused a total of $2.4 billion in property damages. The health effects of the Three Mile Island accident are widely, but not universally, agreed to be very low level. The accident triggered protests around the world.