CHICAGO -- Wednesday marked the 50th anniversary of the Mickelberry Foods Factory explosion that killed nine people including four firefighters.
A memorial service was held Wednesday in the Back of the Yards neighborhood to remember those Chicago heroes.
Chicago Fire Department Commissioner Jose Santiago attended the memorial.
"I salute the families here today as we remember the day the gates of hell opened up," he said.
As many as 70 people were injured after a gasoline truck in a back alley ignited at 49th and Halsted.
Hundreds of day shift workers at the food plant had left for the day 30 minutes before the explosion.