The largest and most visible buildings remaining at the East Tennessee Technology Park are being removed.

Demolition is under way on the Centrifuge Complex, according to the “EM Update” newsletter published last week by the U.S. Department of Energy Office of Environmental Management.

The demolition work is part of the project to finish cleanup at ETTP, the former K-25 site in west Oak Ridge, by the end of 2020. One of the three main sites in Oak Ridge, K-25 was built as part of the Manhattan Project, the top-secret federal program to build atomic weapons during World War II. The site continued to enrich uranium for nuclear weapons and commercial nuclear power plants through the Cold War. Its operations ended in the mid-1980s, and the site is now being converted into a private industrial park.

The Centrifuge Complex has more than 235,000 square feet, and sections of it reach heights of 180 feet. It was built in stages to develop and test centrifuge uranium enrichment technology, the “EM Update” said. The last of these facilities ceased operation in the mid-1980s.