To view our videos, you need to
enable JavaScript. Learn how.
install Adobe Flash 9 or above. Install now.

Then come back here and refresh the page.

Police say the explosion appears to have been started by a fire in an electrical transformer in the building at Sixth Avenue and 20th Street.

Witnesses say just before 11 a.m. they saw a fire ball shoot up the entire building.

"I started walking down the block, you just [saw] people making crazy faces. As soon as I turned around, I [saw] a fireball that had shot up at least past the building," said David Suich, a student at Apex Technical School.

"It was very intense being on the seventh floor and looking out the window and seeing really, really red, hot flames," said Jules Panopoulos, a worker at the building.

"We were all at our desks and we looked up and we saw a ball of fire by the perimeter windows and we implemented our contingency plan right away," said another building tenant.

Firefighters were called to the scene more than 30 minutes before the explosion to put out a manhole fire. When they arrived, they evacuated the entire area, which probably ended up preventing any injuries in the subsequent blast.

"When we get snows like this and use of salt, which is used by the Sanitation Department to make the streets safe, all of that stuff actually starts melting, running off and feeding into these electric vaults," said FDNY Chief James Daly.

Metropolitan Transportation Authority officials say subway service was not affected.