2 Firefighters Killed Battling Chicago Blaze

Dec. 22, 2010: The injured included firefighters who rushed in to rescue their trapped colleagues.

Dec. 22, 2010: The men who died were among four firefighters buried in debris when the South Side building's roof and one wall collapsed. (AP2010)

Dec. 22, 2010: The tragedy came on the 100th anniversary of a grim milestone in U.S. firefighting history, the Union Stock Yards fire, which killed 21 Chicago firefighters. (AP2010)

Dec. 22, 2010: The one-story brick commercial building had been abandoned for several years and utilities had long been cut off. (AP2010)

Dec. 22, 2010: The fire's cause was uncertain but that it was possible that squatters had been living in the building and been burning debris inside to keep warm.