Demolition of the last of five buildings (K-27) at the US Department of Energy's (DOE's) former Oak Ridge Gaseous Diffusion Plant in East Tennessee was completed on 30 August, ending a 10-year programme to remove all the former uranium enrichment buildings at the site. Work to demolish K-27 began in February.

The first gaseous diffusion uranium enrichment facility established at Oak Ridge, K-25, was built in the early 1940s to supply and produce highly enriched uranium (HEU) for the nuclear weapons. In 1945, K-25 was the largest building in the world. By 1955 the complex included five gaseous diffusion buildings – K-25, K-27, K-29, K-33 and K-31 – and continued to produce HEU for US defence programmes and low-enriched uranium for civil nuclear power reactors until the mid-1980s.

The plant was finally shut down in August 1985 and the DOE formally terminated enrichment operations at the site in 1987, when it was renamed the East Tennessee Technology Park (ETTP). The DOE's Office of Environmental Management began the work of cleaning up ETTP in 1989. Demolition of the K-25, K-29, K-33 and K-31 buildings was completed between 2006 and 2015.

The demolition of the last of the former gaseous diffusion enrichment buildings completes Vision 2016, DOE's goal to remove all of the former uranium enrichment buildings at the site by the end of 2016. Oak Ridge Office of Environmental Management said it also marks the first time a former uranium enrichment complex anywhere in the world has been cleaned and demolished.

Cleaned areas of land are being transferred to the City of Oak Ridge and the Community Reuse Organization of East Tennessee, which are working to transform the site into a private-sector brownfield industrial complex. Oak Ridge Office of Environmental Management manager Sue Cange said completion of Vision 2016 made 300 acres (12 hectares) of land available for future development. Work will now continue towards the Vision 2020 goal for the entire ETTP site to be cleaned, reindustrialized and transferred to the private sector by 2020. URS-CH2M Oak Ridge has been DOE's cleanup contractor for the site since 2011.