It’s been four decades since the country’s worst nuclear accident in Three Mile Island, Pennsylvania. NBC's Andrea Mitchell, who covered the emergency in 1979, returns to speak with residents and others about the accident and its impact. | NBC Nightly News with Tom Llamas

What happened at Three Mile Island was the most significant accident in U.S. commercial nuclear power plant history. ☢️ Don't miss #DeadlyEngineering tonight at 9p on Science Channel. | Science Channel

What happened at Three Mile Island? 40 years later the effects of the nuclear meltdown are still debated. An Inside Edition producer looks back on those days in 1979. https://ietv.co/2YL3Fp8 | Inside Edition