The fire happened soon after Maldonado and the team had taken the victory photo in front of the garage.
Williams team chief Frank Williams, who is a paraplegic, was rushed from his wheelchair as he was giving a celebratory speech. It was his team’s first F1 victory in eight years and it coincided with his 70th birthday celebrations.
A black, acrid haze came flowing out of the British team’s garage, filling the paddock and pit lane. Mechanics and track firefighters were quickly on the scene to put out the fire. An ambulance on the scene treated one person for what appeared to be smoke inhalation.
The person with serious burns was airlifted to a Barcelona hospital while five others were taken to a local hospital for smoke inhalation. Ten people were treated at the Catalunya Circuit for smoke inhalation before being released.
The Williams team said the person airlifted to hospital was one of its staff, and three others also received treatment.
F1 team Caterham said team employees were among those taken to the track medical center. One had a minor hand injury; three others had respiratory issues.
Williams driver Bruno Senna’s car was torched by the blaze.
The fire marred a special day for Maldonado, who held off Fernando Alonso to win.
Maldonado started from the pole and withstood the challenge by Alonso’s Ferrari to take the 66-lap race at the Catalunya Circuit by 3.1 seconds.
Maldonado is the first Venezuelan winner in F1. This was Williams’ 114th triumph but first since the 2004 Brazilian GP.
“It’s a wonderful day for me and the team. An unforgettable race,” said Maldonado, who was hoisted onto the shoulders of Alonso and Kimi Raikkonen before being doused in champagne.
“It was a tough race, with the strategy and a couple of laps we were struggling. But the car was so competitive from the first lap.”
Raikkonen made up nearly 20 seconds over the final stretch to finish 3.8 seconds behind Maldonado in third, ahead of Lotus teammate Romain Grosjean. Lewis Hamilton, demoted from pole to last place in the 24-car field because of a rule breach, finished eighth for McLaren.
Kamui Kobayashi, of Sauber, was fifth, ahead of two-time defending F1 champion Sebastian Vettel, who charged past Nico Rosberg’s Mercedes to take sixth after the Red Bull driver had to do a drive-thorugh penalty during the race.
Maldonado drove with confidence down the final stretch despite Alonso bearing down on him. It was Alonso’s fourth runner-up finish in Barcelona to go with a 2006 victory.
Michael Schumacher, in the midst of a terrible season, failed to finish for the third time. He hasn’t won a race since the 2006 Chinese GP, with his last top-three finish also coming in Shanghai. His best finish for Mercedes has been fourth.