A major incident was declared in South Wales after a “loud explosion” was heard before a large fire broke out at a gym on an industrial estate.

The affected building is at risk of collapse, the fire service says.

South Wales Police said one person is unaccounted for but there are currently no reports of serious injuries.

Roads around Severn Road in Treforest are expected to remain closed into the morning.

Hospitals in the areas were on high alert for hours and warned people not to come to A&E unless absolutely necessary. The alert has now been lifted.

In a statement South Wales Police also warned residents to keep windows and doors closed.

Late on Wednesday evening Deputy Chief Fire Officer Dewi Rose said: “At 7.05pm this evening SWFRS responded to repeat calls about an explosion at Mindset Gym, Rizla House, Severn Road on Treforest Industrial Estate, Pontypridd.

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“SWFRS currently has 16 pumping appliances, a number of special appliances and officers in attendance. The latest from the scene is that the building, a large multi-use use two storey, commercial premises, is totally alight and at risk of collapse.”

A spokesperson for the Welsh Ambulance Service said three patients were treated at the scene before being discharged.

Pic: Valley Times
Image:
Pic: Valley Times

Scott Yorath works at Petwise near the location of the fire. He told Sky News he finished work at 5.30 but a friend stayed later.

“They witnessed the explosion and witnessed the metal roller shutters being blown off the building.”

Mr Yorath said he had “never seen anything like this before” and that it was “like being in a movie”.

“This is something that makes your heart pump a little bit faster than what it should be doing really,” he said.

“I’ve never seen so many ambulances, so many police cars, in all my life.

“I think every emergency service vehicle in South Wales is here in Treforest tonight.”

Local councillor Karl Johnson told Sky News he believes the front of the building has been “completely destroyed” and a nearby car dealership also potentially affected.

More than 15 police cars and 10 ambulances were deployed to the scene, with support from the fire service, Mr Johnson said.

‘Loud explosion seems to have triggered fire’

Rhondda Cynon Taf-based radio station GTFM reported that a listener had called in after hearing “a loud explosion which seems to have triggered a large fire”.

Wales Online quoted witnesses as saying they heard a “massive bang” which shook houses, with one adding: “Must have been a big explosion.”

Pic: Twitter / @Jo_Reggelt
Image:
Pic: Twitter / @Jo_Reggelt

Jonny Foxhall, 36, the owner of nearby music venue, Green Rooms, told the PA news agency: “Our front door was flung open so we went out to see what had happened.

“We could see a smoke cloud and an orange glow from above the treeline quickly followed by flames.”

He added: “To feel the shockwave from the explosion is something I’ve never experienced before.”

Bus operator Stagecoach South Wales has said its 132 and 120 services are unable to serve Rhydfelin and Hawthorn on their return journey due to the incident.

Heledd Fychan, Welsh Senedd member for South Wales Central, has described the images and reports of the incident as “hugely concerning” – and urged people to heed warnings to avoid the area.