Source: Knoxville News Sentinel | Mike Blackerby | August 30, 2016

Final demolition of the K-27 building at the old K-25 plant in Oak Ridge on Tuesday, Aug. 30, 2016. (MICHAEL PATRICK/NEWS SENTINEL)

The final wall of the old Building K-27 was taken down by demolition workers this morning, signaling the milestone end of the massive gaseous diffusion complex built more than 70 years ago as part of the top-secret Manhattan Project.

National, state and local officials joined U.S. Department of Energy representatives and 1,500 employees in a send-off to the last of five main buildings slated for demolition at the former K-25 site.

The U-shaped complex, once the world’s largest building housed under one roof, was built at a cost of $512 million in the early 1940s to produce weapons-grade enriched uranium.

K-25 produced the enriched uranium for the atomic bomb that was dropped on Hiroshima that helped end World War II.

Tuesday’s celebratory event at the East Tennessee Technology Park, formerly known as K-25, was titled “Enriching our Future: A Historic Moment.”

U.S. Sen. Lamar Alexander said Tuesday’s symbolic event bridges the past and the future.

“Today marks the end of an era, and I am extremely proud of the men and women who have worked here for more than a decade to complete the demolition of the uranium enrichment buildings and clean up the East Tennessee Technology Park,” said the Maryville Republican.

“Oak Ridge is an example of how cleanup should be done.”

Alexander said the final demolition paves the way for future economic development at the old K-25 site.

The demolition of Building K-27 was the culmination of a 10-year process, Vision 2016, that included the razing of buildings K-25, K-29, K-31 and K-33.

According to officials, Tuesday marked the first time in history that all of a site’s uranium-enrichment gaseous diffusion buildings have been demolished.