Carter complied. She was just a few blocks away when she heard the explosion.

The gas sent flames a few stories high into the night sky. More than 100 firefighters responded, Berardi said.

Dr. Leonardo Lozada heard the explosion a block and a half away at St. Luke's Health Systems, where he is chief physician.

"It was pretty loud. I just heard it; it wasn't that traumatic," he said.

The restaurant's owner, James Frantze, was in Oklahoma at the time of the blast. A message on the restaurant's Facebook page made a simple request of patrons:

"Please keep our friends and families in your hearts and prayers."