The incident happened Saturday at Toronto's Downsview Park while crews were setting up for a concert.
A stage collapse at Toronto's Downsview Park killed one person and injured at least three others setting up for a Radiohead concert, the CBC reported, citing emergency responders.
One person was transported to Sunnybrook Hospital in serious condition while two others were being assessed at the scene, CBC said.
Downsview Park tweeted that the concert was canceled. Show promoter Live Nation Entertainment also announced the show was canceled.
The collapse occurred at 4 p.m. ET, about an hour before venue gates were scheduled to open.
The man who was killed was briefly pinned under the scaffolding and succumbed to a "crushing injury," an official with Toronto Fire Services told CP24.
"From what I understand the piping which makes up the roof structure where lights and what not are supported collapsed down and there was workers setting up the stage at the time," Toronto Fire Services Captain Mike Strapko told broadcaster CP24.
"The big question is how and that is something we will be working closely with the Ministry of Labor on," Constable Tony Vella told reporters at the scene Saturday night.
Stage before and after collapse.
Radiohead was scheduled to take the stage a little after 9:30 p.m., CP24 said.
The Weather Channel reported mostly sunny conditions with moderate winds of 5 to 10 mph ahead of the collapse.
Police said a considerable crowd was already waiting for the show when the stage collapsed, CBC reported.
One witness said he "saw the scaffolding around the stage collapsing in on itself and heard the sound of metal hitting metal and within five seconds it was over," CP24 reported.
The park frequently hosts concerts, and 40,000 people were expected for Radiohead's sold-out show, CBC said. The opener was to be Canadian act Caribou.
Radiohead fans expressed dismay on the British modern rock band’s message board.
“So many people lose in this,” said one post by a person calling herself Miss Modular.
“Oh no Person who died today won't get his/her life back,” said a post by spoll.
On Aug. 13, 2011, the Indiana State Fair stage fell, killing seven in a crowd awaiting a Sugarland concert when a windstorm blew in.
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