A major blaze in Nottinghamshire involving hundreds of tyres is being treated as suspected arson.
Emergency services were called to a scrap yard on an industrial site in Ranskill at 10:23 BST on Friday.
Fire crews have said they will be there for the rest of the weekend.
Police said a full investigation would start when the flames were out but early inquiries had revealed a group of young people were seen letting off fireworks just before the fire started.
On Friday a column of black smoke could be seen for miles and residents were advised to keep windows and doors closed.
Nearby business premises were evacuated and damage was also caused to outbuildings and power lines, police said
Insp Matt Scott said: "We are continuing to work closely with Nottinghamshire Fire and Rescue Service and a joint investigation will be launched to establish the circumstances of how the fire began.
"While the cause is still unknown we are currently treating it as suspected arson after it was reported a group of young people were seen letting off fireworks just before the fire started."
The fire service said the blaze had been "vastly reduced" overnight but work would continue for days.
At its height 14 fire engines were on scene, along with support vehicles.
Incident Commander Damien West tweeted: "Hard work by crews has made great progress in difficult conditions meaning the fire has been vastly reduced by first light this morning.
"Efforts continue today. Great work by all involved."
East Midlands Ambulance Service and Environment Agency teams also attended, with two people treated for smoke inhalation.
Nottinghamshire Fire and Rescue Service thanked colleagues from Derbyshire, South Yorkshire, and Lincolnshire for their help.
It also thanked local businesses and the community for their "patience and understanding for the disruption of the fire has caused".
Local road closures remain in place.