One person is unaccounted for, at least one building has been destroyed and a major incident was declared after an explosion at an industrial estate in South Wales.
Flames and smoke were seen after a fire broke out at a property on Severn Road, Treforest Industrial Estate, at around 7pm on Wednesday.
The two-storey building was "totally alight" and "at risk of collapse", South Wales Fire and Rescue Service said.
Three people were treated at the scene before they were discharged, a Welsh Ambulance Service spokesperson said.
Local NHS emergency departments were on "high alert" after the blaze, with people asked not to attend A&E unless "absolutely necessary".
There are no reports of any serious injuries, however one person remains unaccounted for, South Wales Police said.
Significant road closures remain in place and the public is requested to avoid the area.
Deputy chief fire officer Dewi Rose said: "At 7.05pm this evening South Wales Fire and Rescue Service (SWFRS) responded to repeat calls about an explosion at Mindset Gym, Rizla House, Severn Road on Treforest Industrial Estate, Pontypridd.
"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 two-storey commercial premises, is totally alight and at risk of collapse."
Integer Telecom, a telecommunication provider, said in a Facebook post its building was destroyed in the explosion, adding: "All our staff are safe and unharmed and business will resume as normal."
Cwm Taf Morgannwg University Health Board said: "Due to the ongoing incident at Treforest Industrial Estate this evening, all of our emergency departments are currently on high alert.
"Please help us by not attending A&E unless absolutely necessary. We need to be able to provide care to those who need it the most."
Witnesses at the scene have reported hearing a large explosion.
One, Krishnaraj Nadarajah, the manager of a nearby petrol station, told the BBC: “It felt like it was an earthquake or something. We went outside and there was a fire starting to build up, it was a huge fire and smoke.”
Jonny Foxhall, 36, the owner of nearby music venue Green Rooms, added: "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."
In a statement, South Wales Police said it was a “serious” incident, and that roads nearby are “expected to remain closed for some time.”
Driving past the large fire right now in Treforest Industrial Estate in South Wales. Smoke can be seen all around and large glow. Follows reports of an explosion (taken from passenger seat) pic.twitter.com/3dTK8E6Gjz
— James Briggs (@jamescbriggs) December 13, 2023
The part of the estate where the fire is located is home to a number of businesses including a car dealership, a pet shop and a gym.
Local councillor Karl Johnson told Sky News the front of the building at the estate had been “completely destroyed” by the explosion.
Over 15 police cars and 10 ambulances were sent to the scene alongside the fire service, Mr Johnson said.