PA MediaThe firefighters who died in a blaze at Bicester Motion have been named as Jennie Logan and Martyn Sadler, while the member of the public who died is David Chester.
Police said both firefighters worked at Oxfordshire Fire and Rescue Service and Mr Sadler was also part of the London Fire Brigade.
Ms Logan, 30, and Mr Sadler, 38, died after explosions were heard at Bicester Motion on Thursday, Thames Valley Police said.
David Chester, 57, from Bicester, was also killed, the force added.
Two firefighters sustained serious injuries and remain in hospital, Oxfordshire County Council said.
At the height of the fire, 10 fire crews were tackling the blaze.
The police have commenced an unexplained death investigation, but are not currently treating it as a criminal matter.
Assistant Chief Constable Tim Metcalfe described it as “an absolute tragedy” and said the thoughts of everyone at Thames Valley Police were with the families, friends and colleagues of those who had died.
The force confirmed that officers will remain at the scene for a number of days to ensure the public remain safe.
PA MediaAt the scene today, a visibly emotional Chief Fire Officer Rob MacDougall said he spoke with “a heavy heart” when he confirmed the deaths.
He added: “Our thoughts are with the family friends and colleagues affected during this time.
“I’m immensely proud and grateful for the exemplary multiagency response and the unwavering bravery demonstrated by the emergency services personnel.”
London Fire Commissioner, Andy Roe said: “This is clearly an incredibly difficult time for us all; we have lost a well-respected and much-loved colleague who exemplified courage and selflessness in the service of others.
“Our thoughts are with all the families, friends, and colleagues impacted by this tragedy. We are doing everything we can to provide support to Martyn’s family and colleagues.
“It has been an incredibly challenging day for the UK Fire and Rescue Service. This incident highlights the high-risk nature of the service we provide every day.
“I ask that everyone respects the family’s privacy and gives them the space to grieve.”
“Our sincere condolences go out to Oxfordshire Fire and Rescue Service who also sadly lost a firefighter at this incident, with a further two colleagues in hospital.”
Paying tribute, Prime Minister Sir Keir Starmer said his thoughts were with the families and friends of those who had died following the “devastating news”.
He said: “The bravery of our firefighters is astounding. Hoping those in hospital make a full and swift recovery.”
Conservative Party leader Kemi Badenoch described it as “an absolutely horrifying incident”, adding: “I hope that we can get to the bottom of exactly what’s caused this and make sure that it doesn’t happen again.”
Sherine Wheeler, chief executive of the Fire Fighters Charity, told BBC Radio Oxford everyone in the firefighting community was feeling “heartbroken”.
“It’s very rare and tragic to have the loss of two firefighters alongside a member of the public and I think the impact of that is being felt deeply,” she said.
“For a lot of people who serve in the fire service it brings the reality of the risks they hold crashing home.”
People, including members of South Central Ambulance, have left floral tributes to those affected by the incident at nearby Bicester Fire Station.
Jamie Jessett, from the town, said he went to school with one of the firefighters who died.
He said the fire was “devastating”, but also that it was “amazing” to see the community come together to pay their respects.
“That’s what we need, especially at this moment in time,” he added.
