Crowds at Elrow Town in East London were sprayed with a 'noxious' 'mystery substance' on Saturday evening, leaving some unable to breathe.
The incident occurred between 8pm and 9pm during a set by Jamie Jones. Festival-goers reportedly panicked and fled the stage. The substance was thought by attendees to be either tear gas or pepper spray, the Mirror Online reports. Punters coughed and tasted '"toxic" when they breathed it in.
"We were dancing and all a sudden I was coughing," said Ellis who was affected by the substance.
"I realised that every time I took a breath it just made me want to cough even more. My eyes were watering but I couldn't believe there was anything wrong - I just thought there's no way anything dangerous would happen at a festival."
"We got to the outskirts the crowd and some security guards came running over wanting to know what had happened. I told them, 'I don't know, but everyone's coughing and crying and no-one can breathe'. No one knew what was going on, but they soon established it was some sort CS gas tear gas] that someone had thrown. I've only ever seen it used in riots on the news."
The Mirror Online reports that witnesses they spoke to agreed security had been excellent throughout the evening. Extensive bag checks occurred on arrival and stewards patrolled the sit.
The two day event at the Queen Elizabeth Olympic Park happened over this weekend (August 19 and 20) with Seth Troxler, Shadow Child and Idris Elba playing. Elrow have not yet issues a statement and the Met Police confirmed there were no reports gas used.
There has been no comment from Elrow as yet and the Met Police confirmed there were no reports gas used.