Eleven people were injured, one critically, when eight female acrobats plunged to the ground after the apparatus from which they were hanging by their hair collapsed at a packed circus.
The team with the Ringling Bros and Barnum & Bailey Circus crashed up to 12 metres when the rig tethering them gave way at the Dunkin' Donuts Centre in Providence, Rhode Island.
The acrobats hit the ground just after starting their "hair- hang" routine and the ringmaster telling the audience, "Suspended only by the strength of ...," a video posted online showed.
The performers did not scream as they fell, but there was a "collective gasp" from onlookers who were unsure at first whether the collapse was part of the act, said spectator Aletha Wood, who was at the show with her two children and took the video. Stephen Pare, the Providence public safety commissioner, said the injured were treated at Rhode Island Hospital.
"They're in a critical condition, but they are non-life-threatening injuries - a lot of broken bones, etc," he said.
A performer below them on the floor was also badly injured, fire officials said.
Wood said the collapse stunned the audience. "It was a pretty packed house," she said.
Providence Public Safety Commissioner Steven Pare told WPRO-AM yesterday that the clamp that held the performers to the rafters failed. He said federal workplace safety investigators were focusing on why it failed.
Stephen Payne, a spokesman for Feld Entertainment, the parent company of Ringling Brothers, said that because the performers were attached to the equipment and could not let go of it, a safety net should not have been required.
Wood's video showed the performers at the start of the routine hidden by a cloth cover lit by blue and red lights.
The cloth fell away to reveal the acrobats dressed in sequined costumes and hanging from a circular canopy apparently suspended by a cable.
One of the performers was suspended beneath the rest.
The structure then suddenly crashed to the floor. Workers and emergency personnel rushed to the acrobats, with a stretcher arriving a couple of minutes later after the lights were dimmed. The Labour Department's Occupational Safety and Health Administration said its inspectors were at the scene to determine if there had been any safety violations.
Payne, the Feld spokesman, said the firm was working with authorities to make sure the apparatus was safe.
"Safety is our top priority, not just for our performers but also for our crew and all the families who come to see a Ringling Bros performance," he said.
Ringling's other two shows for Sunday were cancelled, along with last night's show.
Lee Kaplan, a product liability lawyer in Houston, said the fact that hundreds of spectators witnessed the accident opened up the possibility of claims being filed on behalf of children who could have been traumatised.
Kaplan said possible defendants ranged from the circus to the maker of the apparatus.
Tom Lyons, a Providence lawyer, said injured performers could file a workers compensation claim against the circus.