A British cameraman was hurt after being hit by a loose wheel following a botched pit stop involving Red Bull's Mark Webber at the German Grand Prix.
Webber's right rear wheel came off as he pulled away from his pit box and hit cameraman Paul Allen, who suffered a broken shoulder and cracked ribs.
The incident happened on lap nine of the 60-lap race at the Nurburgring.
Allen, who works for FOM, Formula 1's in-house broadcaster, was taken to hospital and kept "under observation".
A statement from the FIA, the sport's governing body, said: "Paul Allen was hit on the left-hand side.
"Remaining conscious, he was treated at the circuit medical centre and then transported by helicopter to Koblenz Hospital.
"The Briton has been kept there, under observation. Further information from the hospital will be provided as soon as it becomes available."
Red Bull team principal Christian Horner said: "The most important thing is that the cameraman who got struck by the tyre does not appear to have suffered serious injury.
"It's a timely reminder that working in the pit lane is dangerous."
Formula 1 safety has been prominent in the headlines since multiple tyre blowouts at last weekend's British Grand Prix raised fears about drivers being hit by flying debris.
Webber, 36, came into the pits for a routine tyre change but his crew took longer than usual because of a problem with the right rear tyre.
He was released without the wheel being secured properly and it broke free and bounced into Allen, knocking him flat on his back.
As Allen was tended to, Webber was told to turn off his engine and his three-wheeled car was pushed back to the pit box by his mechanics, where he was finally sent on his way, albeit a lap down.
The Australian recovered to finish seventh in a race won by team-mate Sebastian Vettel.
Former world champion Damon Hill told Sky Sports: "It was horrible.
"It was inevitable it [the wheel] was going to hit someone because we could see it bouncing down the road. It was like playing skittles.
"It is asking too much to expect everything to go well in the pit lane. It's a dangerous place. Mistakes will happen."
There was more drama on the 24th lap when a small fire broke out at the back of Jules Bianchi's Marussia.
The Frenchman was forced to jump out of the car, which then rolled backwards across the track before coming to a stop on the grass.