Large plumes of smoke were filmed coming from one of the Bicester Motion buildings
Two firefighters and a member of the public have died following a large fire at a former RAF base.
Oxfordshire County Council said the firefighters died while tackling the blaze at Bicester Motion on Thursday.
Two further firefighters suffered serious injuries and are in hospital, the council added.
Chief fire officer Rob MacDougall said: "It is with a very heavy heart that we today report the loss of two of our firefighters. Families have been informed and are being supported."
James Matthews
Thick black smoke billowed from the site on Thursday evening
Ten fire and rescue crews were called to tackle the blaze on Thursday at about 18:30 BST.
The council said four crews remained at the scene of the fire, which is now under control.
Officers stayed at the entrance of the former RAF base on Friday, and a fire engine and ambulance could be seen leaving the area while another police vehicle entered the site.
Eyewitnesses described seeing black smoke in the sky from the other side of town.
Bicester Motion is home to more than 50 specialist businesses, focused on classic car restoration and engineering.
It is on the site of RAF Bicester, a former bomber station.
The cause of the fire is not yet known.
PA Media
Ten fire and rescue crews were called to tackle the blaze