The MCC has also concluded that commercial reactors of the type now used in the United States have a sound safety record, even considering the accident at Three Mile Island (TMI), and that there is no credible evidence that there has been harm to health by these reactors. MCC further concluded that the hazards of transporting used nuclear fuel have been badly exaggerated, and that recent proposals about the storage of used fuel will reduce the technological difficulty of construction a long-term repository.