Sounds like it could of been much much worse. The construction workers and firefighters cleared everyone out of the buildings as soon as they discovered the gas leak... before the big explosion.
My sister's office is across the street. She had just walked down to the bagel shop because there were multiple fire trucks to ask if they should evacuate, firemen said no. Right after she got back to the office, the explosion blew the door in and several of the windows. Knocked everyone down or against the back walls. No serious injuries for them apparently.
