(CNN) -- A steam pipe explosion during Midtown Manhattan's rush hour Wednesday shattered New Yorkers' nerves. Moments after the blast, I-Reporters sent photos and video showing a huge steam plume rising into the air. The explosion scattered debris and fogged the city's storied skyline, causing many to fear they might be in danger.
Julia Ofman took this photo from her balcony showing a rising plume of steam in New York.
"It was like a volcano," said New Yorker Jonathan Thompson, whose video captured the loud rumbling of the steam as it shot into the sky.
Ben Alden, 23, used his iPhone to send some of the first images captured from the scene. From the 18th floor of his office building, blocks from Grand Central Station, he heard a "deep rumbling sound" and saw steam rising up past buildings.
He said he tried to rally his co-workers to get out, and they got away on foot. Outside, he saw a massive exodus from nearby buildings.
"People were standing around, wondering what was going on," he said. "There seemed to be a general confusion over whether it was a terrorist attack or not."
Similar concerns were echoed by Julia Ofman, who will soon be 14, who was alarmed when her mother looked out the window and saw people running in the street. They hadn't heard anything, but their thoughts immediately turned to fears of a situation comparable to September 11.
She said they ran out to the balcony and saw the rising steam. Ofman said she took photos and wanted to go to the rooftop to get a better view, but her mother said they needed to stay inside because the air might be unsafe to breathe.
Brett Macune works in the MetLife Building next door to where the explosion happened. He said the building's alarm system sounded and people started rushing for the exits, but an announcement shortly afterward advised workers to remain calm and stay inside the building.
Visitors weren't immune from the shock either. The explosion kicked off a vacation that Dodd Jindra, 19, said he will never forget. He said he lives on a remote Colorado ranch and was in New York with his family to begin a trip through Europe.
Hours after settling into a hotel room, Jindra said he heard a sound like thunder. He and his family decided to take an elevator down from the 38th floor because they thought the stairs would be too difficult.
He said the elevator stopped at almost every floor as terrified people tried to find an escape route. When he got to the street, he took as many pictures as he could, adding that the crater left behind by the explosion is visible through his hotel window.
"I thought we were in 9/11," Jindra said. "I don't know. It's definitely a memorable experience." E-mail to a friend