Jason Olson, Deseret Morning News
Former Key Bank tower is to be imploded on Aug. 18.

For the first time since 1983, a Salt Lake City building will be imploded this summer.

The former Key Bank tower at 50 S. Main is coming down as Property Reserve Inc., the real-estate arm of The Church of Jesus Christ of Latter-day Saints, makes way for the City Creek Center development.

PRI said Wednesday that Okland Construction Co., which is handling the construction work on the Crossroads Plaza block, has received permission from the Utah Air Quality Board to bring the building down with implosion.

"Worker safety, combined with cost and time savings, make implosion the preferred method of demolition," City Creek Center spokesman Dale Bills said in a statement. "Implosion also limits public inconvenience to one day, as opposed to four to five months."

Okland currently plans to bring the tower down on the morning of Aug. 18. That is a Saturday, so the downtown blocks won't be as busy as they would be during a normal work day. The date could change, based on site preparation and weather conditions.

Bryce Bird, air-standards branch manager for the Utah Division of Air Quality, said Okland officials had to present the board with details of their plans for the implosion.

"There will be dust," he said. "It will be a short-term episode."

Buildings are imploded by strategically placed explosions within the building. Those explosions take out key pieces of the building in a way that causes the upper levels to fall inward, so the building collapses on its own footprint and doesn't impact neighboring buildings.

Bird said Okland needed permission from the Air Quality Board because the company was asking for a variance from a rule that limits the dust output that normal construction work can cause.

"It's basically a balance," Bird said of the factors weighed in the decision to allow the implosion. "Because the building is so big, it would take months to deconstruct it from the top down and would tie up traffic downtown for months."

Bird said Okland crews will seal off ventilation systems in nearby buildings and evacuate neighboring tenants who have respiratory problems, among a host of other mitigation efforts.

City Creek Center is a proposed 20-acre mixed-use development that will replace the Crossroads and ZCMI Center malls with an indoor-outdoor mix of retail, residential and office space. The new development is set to open in 2011.

Construction crews have been bringing down buildings on the Crossroads block for several months, beginning with the Inn at Temple Square and moving toward the southeast. Those buildings and parking structures have come down with crews and heavy machinery knocking them down wall by wall, piece by piece.

The Key Bank tower will be the last building on the block to come down. The Marriott Hotel, Gateway Tower West and the Crandall and McIntyre retail buildings will remain standing on the block.

Deconstruction has yet to begin on the ZCMI block, although it is expected to start soon.

The last building to be imploded in Salt Lake City was the Hotel Newhouse at Main Street and 400 South in June 1983. In August 2000, two smokestacks in Murray were imploded. A collection of buildings and smokestacks at the Geneva Steel in Vineyard were imploded in July 2005. The old Salt Palace had initially been slated for implosion in 1994 until county officials decided to tear it down instead.

The former Beneficial Financial Group tower at 36 S. State St. now bears the name of Key Bank and will be the new site of the bank's corporate headquarters.

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