SUTTON PLACE — A Manhattan ad executive on a first date plunged to her death when the railing gave way on the balcony of her 17th-floor Sutton Place apartment early Thursday, sources said.
Jennifer Rosoff, 35, had stepped out to smoke a cigarette with a man she'd been out on a date with when she fell from Stonehenge 57, at 400 E. 57th St., at about 1 a.m., sources said.
Moments before her fall, Rosoff had propped her leg up on the railing to stretch when it gave way, sources said.
"You know, you shouldn't do that," said her companion, who met Rosoff for the first time that night after talking online, according to sources.
"I do it all the time," she replied moments before the railing collapsed, sending her tumbling onto scaffolding below, sources said.
"I heard a bang. I thought it had been a gunshot," said soda executive Steve Hersch, who lives two doors down.
"It sounded like a 200-pound punch," said Sara Shubert, who lives in Rosoff's building.
Rosoff was pronounced dead at the scene, police and witnesses said.
The man Rosoff had been with ran outside repeatedly screaming, "Oh my God," according to a witness.
"He was hysterical. He was in shock," said another witness who spoke with the man.
The man's parents answered his apartment door and said he was home Thursday, but declined to comment.
Rosoff's sister, Alexis Treeby, was awoken about 5 a.m. with the tragic news, she said.
"She was a lovely person. My children adored her," Treeby said of Rosoff. "She was kind, generous and did charity work."
Most recently, Rosoff was the director of sales for advertising company TripleLift, according to her LinkedIn profile. She had previously worked for various Conde Nast magazines including The New Yorker, Lucky Magazine and Cosmopolitan.
"We are all deeply saddened by the sudden and tragic loss of our dear friend and co-worker," said TripleLift co-founder and CEO Eric Berry in a statement.
"She was well-loved and a highly-respected member of our team. Her tremendous energy and humor brought so much joy to the office. The entire company is distraught by the loss of Ms. Rosoff — she will be deeply missed."
The Department of Buildings ordered all the building's balconies closed Thursday morning, saying conditions there were "imminently perilous to life."
According to a DOB spokeswoman, the agency received an inspection report for the entire facade — including all balconies — in February. Under local law, facades must be inspected once every five years.
The department slapped Stonehenge with a class two aggravated Environmental Control Board violations because of the incident, a spokeswoman said. The property company declined to comment.
An investigation into the incident is ongoing.
With reporting by Murray Weiss, Alan Neuhauser, Heather Holland, Victoria Bekiempis, Mathew Katz, Claire Oliver and Aidan Gardiner.