Williams's celebrations of a first Grand Prix victory in eight years have been marred by injuries to 31 people following a fire in the team's garage.
Three of four injured Williams team members were among a total of seven people requiring hospital treatment.
Four Caterham mechanics and a Force India team member, who had suffered smoke inhalation, were among those treated at the track's medical unit.
The incident is believed to involve a Kers unit, which sparked a fuel fire.
Caterham, who occupied the garage next to Williams in the Circuit de Catalunya pit lane, explained one of those injured had a minor hand injury, with three others suffering respiratory issues.
The fire began at the back of the Williams garage
A Williams spokesperson said: "Four team personnel were injured in the incident and subsequently taken to the medical centre. Three are now receiving treatment at local hospitals for their injuries, while the fourth has been released. The team will monitor their condition and ensure they receive the best possible care.
"The team, the fire services and the police are working together to determine the root cause of the fire."
The fire occurred after Williams's group photo commemorating
Pastor Maldonado's victory
, the Grove-based team's first since Juan Pablo Montoya's win in the 2004 Brazil Grand Prix.
Founder Frank Williams, whose family attended the race in celebration of his recent 70th birthday, was led to safety.
"I was there when [founder] Frank Williams was giving his speech to everyone," said Williams reserve driver Valtteri Bottas.
"I felt an explosion from behind, somewhere from the fuel area, and everyone ran out quickly."
Mechanics from several teams joined Williams's pit crew in attempting to extinguish the flames which sent smoke billowing across the paddock.
Maldonado's car was parked elsewhere awaiting post-race checks during the blaze, but the FW34 of team-mate Bruno Senna, who crashed out after 12 laps, was in the garage at the time.