My friend works directly across the street. No one answered his office telephone number so I assume that either his building was evacuated or they couldn't even get into the office since this happened at 8:30 AM.
I'm in the area and had heard sirens for almost two hours.
The four story townhouse building which exploded contains doctors' offices and a duplex apartment where apparently a doctor lives.
The blast might have been caused by a suicidal doctor.
http://www.wnbc.com/news/9490570/detail.html
ETA: I just heard that my friend who works across the street is fine. It's chaotic in that area.