David Hill and others who work inside the building ran for their lives this morning.
"It literally just engulfed the whole front of the building. You couldn't see anything but flames," hill said.
"Glass shattering and people screaming on our floor to get the hell out," Prena Younis said.
Authorities say the incident started around 10:45 a.m. Firefighters came here after a call about a smoky manhole.
Carol Paplin, who works for an office furniture dealership on the sixth floor of the building said she detected a sulfur odor as she approached the building at 10:30 a.m., but as she got to the entrance the smell faded and she went inside.
Firefighters blocked off the area About half an hour later, building workers were told via the public address system that there was a fire on the sidewalk but not to be alarmed.
"Then, as I walked through the office, an orange fireball went up at our window," Paplin said.
At that moment, another announcement instructed those in the building to evacuate using a back staircase.
"Everyone was calm, although there were many people without their coats and pocketbooks," said Paplin.
Had the fire department not blocked off this busy sidewalk ahead of time, you can just imagine how many injuries, even deaths, might have occurred.
"Day in and day out, we know a smoky vault can be an explosive vault at any minute," Dpty. Chief James Daly said.
They spent the day clearing out the glass from all the windows so the building wouldn't pose any further danger.
A Radio Shack on the ground floor was completely blown out, nearly a hundred people who work in other parts of the building were forced out for the day as well, but most of them were just grateful that the situation wasn't far worse.
"I heard screaming and all I saw was the fire outside the window. I grabbed my coat and ran," Allison Murphy, who works on the fifth floor, said.
Other businesses in the building include a Bally's Total Fitness gym and a Papyrus stationery store. The building also houses the Apex Technical School on the opposite end from where the damage occurred.
The building is part of the Ladies' Mile Historic District, so named for the shops and stores that were along parts of Broadway toward the end of the 19th century. That area was given its designation in 1989.
The structure, known as the Simpson, Crawford and Simpson building, "is an incredibly important building historically and architecturally," said Elisabeth de Bourbon, spokeswoman for the city's Landmarks Preservation Commission.
Done in the Beaux Arts style, the building was constructed at the beginning of the 20th century. It has been used as a department store, a warehouse and an automobile showroom.
Consolidated Edison spokesman Christopher Olert said an investigation was under way into the cause of the explosion.