(I) The accident at the Three Mile Island nuclear power plant 1979 was the most serious in U.S. commercial nuclear power plant operating history. (II) Though it led to no deaths or injuries to plant workers or other people, it caused sweeping changes involving emergency response planning and many other areas of nuclear power plant operations. (III) The accident began about 4:00 a.m. on March 28, 1979, when the plant experienced a failure in the non-nuclear section of the plant. (IV) It also caused the U.S. Nuclear Regulatory Commission to tighten and heighten its regulatory oversight. (V) Resulting changes in the nuclear power industry and at the NRC had the effect of enhancing safety.