A nightclub in Bournemouth was evacuated after a canister of pepper spray was released on the dancefloor, causing panic and adverse reactions among revellers.

As many as 40 people with sickness, coughing fits and itchy eyes were treated at the scene by paramedics after the canister was set off at the Cameo club in the early hours of Saturday morning. One person was taken to hospital as a precaution.

Later Cameo, in a a statement posted on Facebook, said: “Last night there was an incident in the main room at the club where a small canister of pepper spray was set off on the dance floor.

“This was a silly, pointless act and we hope that those of our customers who were caught up in it are feeling better today and are now fully recovered.

“Customer safety is of paramount importance to us. We utilise a combination of searching customers, metal arches and wands – all of which are above and beyond what our licence asks us to do.”

They said it was likely the canister had been in a small plastic container.

Officers called to the incident at 2am said the clubbers, many of whom were freshers, complained of shortness of breath and stinging eyes. It was initially thought the substance might be teargas.

A Dorset police spokeswoman said an “irritant, possibly CS spray”, had been released in the club.

“Following a decision by management of the premises to evacuate, around 40 people were treated by the ambulance service for minor effects,” she said.

Josh Wilde, 20, posted a video on Twitter of the scenes outside the club and said witnesses had told him an object, believed to be a canister, was dropped on the floor inside before everyone started coughing.

I spoke to a police officer and some sort of canister has been let off inside the venue. The emergency services have evacuated everyone until they get to the bottom of it pic.twitter.com/vrwDCubjJD — Josh Wilde (@josh_wilde20) September 29, 2018

The third-year journalism student later told the Press Association the club had recently introduced thorough searches on the door, with airport-style scanners, but only some clubbers had to go through them.

“It had the most security at a club I’ve ever seen outside central London. There were hundreds of people queuing to get in, it was absolutely packed, I queued for at least an hour,” he said.

“I initially thought someone had got on to the stage because security were running around the main room, but then a firefighter rushed past in full gear so I knew it must be something more serious.

“Outside, people were coughing, someone told me all their friends just started spontaneously coughing and crying. There were around two to three ambulances and six or seven police cars and a lot of officers.”

Pictures on social media showed crowds gathered in the street. The rapper Yungen had been performing at the club as part of an event to mark freshers’ week.

Everyone that just come to see me in Bournemouth as I’m sure all of you could see the police shut off my mic without saying anything mid performance because apparently someone sprayed pepper spray. It was so fuckin sick up to that point. I hope everyone’s safe ❤️ — Yungen (@YungenPlayDirty) September 29, 2018

Police said officers had searched the club and found no evidence of any chemical or noxious substance that posed a continuing risk to the public.

The club will open for business as usual on Saturday night. An investigation into the incident continues.