Firefighters respond to a fire after an explosion and building collapse in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. The explosion leveled an apartment building, and sent flames and billowing black smoke above the skyline. (AP Photo/John Minchillo) (AP2014)
Police assist victims following a building explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. The blast happened after a neighbor reported smelling natural gas. (AP Photo/Bebeto Matthews)
A man receives medical attention after an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. The blast happened after a neighbor reported smelling natural gas. (AP Photo/Bebeto Matthews)
Firefighters respond to a fire after an explosion and building collapse in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. The explosion leveled an apartment building, and sent flames and billowing black smoke above the skyline. (AP Photo/John Minchillo) (AP2014)
Firefighters respond to a fire after an explosion and building collapse in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. The explosion leveled an apartment building, and sent flames and billowing black smoke above the skyline. (AP Photo/John Minchillo) (AP2014)
Bomberos trabajan en el lugar en que una explosión provocó que dos edificios se derrumbaran en el vecindario East Harlem de Nueva York, el miércoles 12 de marzo de 2014. (AP Foto/Jeremy Sailing)
Bomberos atienden un incendio en la calle 116, en Harlem, luego de que una explosión en el norte de Manhattan provocó el derrumbe de dos edificios y dejó al menos dos muertos y varios heridos, el miércoles 12 de marzo de 2014, en Nueva York. (AP Foto/John Minchillo)
Firefighters respond to an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. Con Edison spokesman Bob McGee says a resident from a building adjacent to the two that collapsed reported that he smelled gas inside his apartment, but thought the odor could be coming from outside. (AP Photo/John Minchillo)
A police officers wear safety mask a block away from the site of an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. Con Edison spokesman Bob McGee says a resident from a building adjacent to the two that collapsed reported that he smelled gas inside his apartment, but thought the odor could be coming from outside. (AP Photo/Bebeto Matthews) (AP2014)
Firefighters respond to an explosion and building collapse in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. The explosion leveled an apartment building, and sent flames and billowing black smoke above the skyline. (AP Photo/John Minchillo)
Mayor Bill de Blasio, center, arrives to visit the site of an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. Con Edison spokesman Bob McGee says a resident from a building adjacent to the two that collapsed reported that he smelled gas inside his apartment, but thought the odor could be coming from outside. (AP Photo/Bebeto Matthews)
Socorristas llegan al lugar de una explosión que derrumbó dos edificios de apartamentos y provocó la muerte de dos personas en East Harlem, en Nueva York, el miércoles 12 de marzo de 2014. (AP Foto/Jeremy Sailing)
Emergency crews respond to an explosion and building collapse in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. The explosion leveled an apartment building, and sent flames and billowing black smoke above the skyline. (AP Photo/Jeremy Sailing) (AP2014)
In this photo provided by Shane Kennedy, smoke rises from the site of an explosion and building collapse near Park Avenue and 116th Street in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. (AP Photo/Shane Kennedy)
Emergency workers respond to the scene of an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. Con Edison spokesman Bob McGee says a resident from a building adjacent to the two that collapsed reported that he smelled gas inside his apartment, but thought the odor could be coming from outside. (AP Photo/Jeremy Sailing)
Firefighters respond to an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. Con Edison spokesman Bob McGee says a resident from a building adjacent to the two that collapsed reported that he smelled gas inside his apartment, but thought the odor could be coming from outside. (AP Photo/John Minchillo)
Firefighters respond to a fire on 116th Street in Harlem after a building exploded in huge flamesleading to the collapse of at least one building and several injuries, Wednesday, March 12, 2014, in New York. (AP Photo/John Minchillo)
Firefighters respond to a fire after an explosion and building collapse in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. The explosion leveled an apartment building, and sent flames and billowing black smoke above the skyline. (AP Photo/John Minchillo) (AP2014)
Police respond to the scene of an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. Con Edison spokesman Bob McGee says a resident from a building adjacent to the two that collapsed reported that he smelled gas inside his apartment, but thought the odor could be coming from outside. (AP Photo/Jeremy Sailing)
Firefighters respond to an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. Con Edison spokesman Bob McGee says a resident from a building adjacent to the two that collapsed reported that he smelled gas inside his apartment, but thought the odor could be coming from outside. (AP Photo/John Minchillo)
Firefighters respond to a fire after an explosion and building collapse in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. The explosion leveled an apartment building, and sent flames and billowing black smoke above the skyline. (AP Photo/John Minchillo)
A police officers wear safety mask a block away from the site of an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. Con Edison spokesman Bob McGee says a resident from a building adjacent to the two that collapsed reported that he smelled gas inside his apartment, but thought the odor could be coming from outside. (AP Photo/Bebeto Matthews)
Firefighters work the scene of an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. Con Edison spokesman Bob McGee says a resident from a building adjacent to the two that collapsed reported that he smelled gas inside his apartment, but thought the odor could be coming from outside. (AP Photo/Jeremy Sailing)
Firefighters respond to an explosion that leveled two apartment buildings in the East Harlem neighborhood of New York, Wednesday, March 12, 2014. Con Edison spokesman Bob McGee says a resident from a building adjacent to the two that collapsed reported that he smelled gas inside his apartment, but thought the odor could be coming from outside. (AP Photo/John Minchillo)