People had to be evacuated from their homes following a large fire at an industrial unit.
Crews were called to the fire involving several vehicles near Pentrebach Road in Pontypridd at 19:00 BST.
Thick black smoke billowed into the air and eyewitnesses reported hearing several explosions.
John Richards, who lives more than a mile away from the blaze, said thick black smoke could be seen right across the valley.
Police closed local roads as firefighters tackled the flames using specialist equipment. The cause of the blaze is not yet known.
Jennie Griffiths, head of control for South Wales and Mid and West Wales Fire and Rescue Services, said the fire involved a number of vehicles in the unit and a number of cylinders.
She tweeted that there was was “significant structural damage to building”.
Four fire engines and three water bowsers were sent to the scene.
Local resident John Paul Davies said: “The smell was stronger than rubber and I was covered in black soot.
“There was small holes on my t-shirt when ash fell on me. There was also quite a number of explosions going on.”