LONDONDERRY TOWNSHIP, Pa. (WHTM) — Forty-three years ago, Three Mile Island in Dauphin County became the site of a nuclear accident that captured worldwide attention and is considered the worst commercial nuclear accident in U.S. history.

The 1979 partial meltdown in the Unit 2 reactor was the result of both human and mechanical failures, and it led to the evacuation of around 140,000 people. Officials reported low levels of radiation released into the atmosphere during the crisis, which lasted five days.

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TMI Unit 2 has been shut down since that accident in 1979, and Unit 1 went offline for good in 2019. As of March 2022, officials say all nuclear waste at Unit 2 has been removed and is offsite. Now the focus is on decommissioning the unit, which is a process that will take many years to complete.

TMI Unit 2 officials say they’re currently in the first phase of the decommissioning process, which is focused on planning. Demolition of the cooling towers will come later.

Units 1 and 2 are owned by two different companies, each responsible for decommissioning their own unit.