The organiser of a fireworks display on Sydney's northern beaches says a faulty device is responsible for sending pyrotechnic pellets into a crowd gathered for Christmas carols.
An 11-year-old boy was among nine people who had to be treated by emergency services following the event at Allambie Heights Oval just before 10pm on Sunday night.
Police said a firework shot into a crowd of people during the event.
Vision of the scene showed people screaming and chaos after the firework went off.
An eight-year-old girl and 12-year-old boy also suffered burns and were briefly hospitalised.
As investigations begin, organiser Christian Howard said a type of firework known as 'roman candles' malfunctioned.
"Which means multiple shots fired causing it to travel into different directions, rather than the desired direction of projecting into the sky," he said.
One witness, Mark Bryant, who was there with his children described it as a terrifying experience.
"It was pretty scary," he said.
"So there was an explosion at the scout hall behind us down here, and one in the bush on the left. The next thing, it's gone towards the crowd.
"I said to everyone before it started, I hope one of these pods don't fall over, they don't look very secure. I just had a premonition.
Mr Bryant said one of the pods appeared to fall over about five minutes after the fireworks started.
"I was on the ground, there was a lot of commotion beside us, kids were running everywhere."
An eight-year-old girl and 12-year-old boy were also hospitalised, but have since been released.
The event organiser, a private events management company, said the arrangement of fireworks was outsourced to Howard and Sons Fireworks.
“While we were engaged to promote the event and secure sponsors and help with event set up (not fireworks), we had no involvement in arranging the fireworks, that was another company,” a statement said.
It's understood the organisers completed all the required paperwork including a licence issued by SafeWork NSW to discharge fireworks.
