A Utah search-and-rescue team will be among the more than 400 firefighters who will spend the weekend digging through the rubble of a demolished Colorado sports arena in what may be the single biggest mock disaster ever held.

"We've had various discussions about whether or not this is the biggest ever done, but no one's really sure," said Mark Amann, spokesman for the Federal Emergency Management Agency, which is sponsoring the event along with the Denver Fire Department. "Obviously this is a once-in-a-lifetime opportunity."

For the past week, a wrecking crew has been chipping away at the 26-year-old McNichols Arena in Denver, reducing the 300,000-square-foot building to a pile of concrete and metal. Mixed among the wreckage are some mannequin "victims" just waiting to be rescued. Firefighters and rescue dogs from Utah, Colorado, Nebraska and New Mexico will participate in the three-day event, Amann said.

As a training exercise for Utah's Urban Search and Rescue Task Force One, the event is invaluable, said Salt Lake County Fire Capt. Mike Riley, who is leading the squad of 18 on the trip. Seven of those attending are Salt Lake County firefighters, six are Salt Lake City firefighters and three are members of the Rocky Mountain Rescue Dogs.

"We meet and train once a month, but we've never had a chance to do anything like this," Riley said. "It's a chance to hone our skills and learn some new ones that we'll bring back and share with the rest of the task force. But we also take those skills back to the rest of our departments. It makes us better firefighters."

Utah's Task Force One is one of 27 FEMA-sponsored groups nationwide that are deployed across the country or around the world after disasters. Task force members served in Oklahoma City after the 1995 bombing, in Florida following Hurricane Floyd and more recently in Turkey following massive earthquakes, Amann said.

Utah's task force, which was formed in 1991 and is comprised of more than 60 firefighters from Salt Lake City and Salt Lake County, has never been deployed.

"We've never had anything happen here that we've been needed," Riley said. "That's good, but it's sort of like practicing football all week and then going to the game and sitting on the bench. At some point, you'd like to be able to use what you've learned."

FEMA and Denver Fire are working to make sure this weekend's participants get as "real" an experience as possible, Amann said. Search teams, building engineers and rescue dogs will work together to shore up the crumbled arena in order to safely excavate it and rescue the "bodies" that have been planted in the wreckage. The exercise would not be possible without the foresight of the Denver Fire Department, Amman said. McNichols, the former home of the Denver Nuggets and the Colorado Avalanche, is coming down to make way for a new stadium for the Denver Broncos.

"The Denver fire department really saw an opportunity here and has been generous enough to share it with these state and federal agencies," Amann said. "These firefighters will go home better prepared to serve their communities."