Excerpts from the ChicagoSuntimes.com:

The Union Stockyard fire on Dec. 22, 1910, claimed the lives of 21 Chicago firemen. A six-story brick wall collapsed on the men as flames fed by grease — a natural byproduct of animal slaughter — swept through the building.

Chicago Fire Department Commissioner Jose Santiago spoke at the memorial service Thursday that took place near the corner of Exchange and Halsted.

A nearby statue depicts firefighters battling the 1910 blaze. Etched on the base of the statue are the names of all firefighters who were killed in the line of duty.

Santiago emphasized that, as it was in 1910, when the fire hydrants froze the night of the fire, winter is a dangerous time to be a firefighter.

Among those who died beneath tons of collapsed brick on that fateful day in 1910 were Captain Dennis Doyle and his son, Truckman Nicholas Doyle. Their deaths came to the attention of Kevin Doyle only after a friend stumbled upon their names on the internet and shared the information.

Kevin confirmed it: His great-great grandfather was Dennis Doyle, who died alongside his son and fellow fireman, Nicholas. His other son, Edward, also a fireman, was at the scene, too, and for 36 straight hours he pulled bricks from the pile of rubble to locate his father and brother.

thanks Dan