By Jennifer Glickel and Nicole Bode
A transformer exploded underneath a Chelsea sidewalk Thursday, blowing the windows of a seven-story building out on to the street below and igniting flames that enveloped the structure, authorities said.
There were no injuries reported during the blaze at 641 Sixth Avenue between W. 19th and W. 20th streets, authorities said. A search of the building was underway Thursday afternoon.
Initially, the FDNY evacuated just the lower floors of the building after receiving a call about a smoking manhole about 10:45 a.m.
The fire, however, quickly spread beneath the ground to other manholes towards 19th Street.
"At thirty-seven minutes in, there was a fireball that shot the windows out of all seven floors out of the building," said Deputy Fire Chief James Daly.
Luckily, no one on the upper floors was hurt and firefighters evacuated the remainder of the building immediately, said FDNY spokesman Steve Ritea.
The fire was brought under control by 12:30 p.m., authorities said.
Daly said Wednesday's heavy snowfall was "a likely culprit" in causing the blaze. He said it wasn't uncommon for melting snow to drip on to a transformer and trigger an electrical fire.
ConEdison was on the scene Thursday afternoon investigating the exact cause.