English: This image depicts the Three Mile Island nuclear power plant near Middletown, Pennsylvania, which was the site of a March 28, 1979 power plant accident. The accident at the Three Mile Island Unit 2 (TMI-2) nuclear power plant was the most serious in U.S. commercial nuclear power plant operating history, even though it led to no deaths or injuries to plant workers or members of the nearby community. It brought about sweeping changes involving emergency response planning, reactor operator training, human factors engineering, radiation protection, and many other areas of nuclear power plant operations. It also caused the U.S. Nuclear Regulatory Commission to tighten and heighten its regulatory oversight. Resultant changes in the nuclear power industry and at the NRC had the effect of enhancing safety.