Dramatic surveillance video captured the moment of the blast.
Nineteen people were hurt, four critically.
It sparked a seven-alarm fire that raged out of control.
Firefighters were still on-scene putting out hot spots Friday morning, reported CBS News correspondent Jericka Duncan.
Two people were unaccounted for, authorities said.
At least 250 firefighters worked to put out the raging fire, which sent a pillar of smoke hovering above the city.
Read more at CBS News –