Philadelphia (Pennsylvania): British IndyCar driver Justin Wilson is in coma after suffering a head injury during a race here.
The ex-Formula 1 driver, who drives for Andretti Autosport, appeared to be hit by debris after a car crashed in front of him and he then hit a wall on Sunday.
The 37-year-old was airlifted to hospital from the Pocono Raceway here.
"Wilson is currently in a coma and in a critical condition," indycar.com said in a statement on Sunday.
"IndyCar sends its thoughts and prayers to Justin, his family, and Andretti Autosport during this difficult time," the statement said.
Wilson appeared to have been struck on the head by a piece of debris from American driver Sage Karam's car after it spun and crashed in front of him on lap 179 of the 200-lap race.
Karam was able to get out of his car and was treated for a foot injury.
Wilson, from Sheffield, competed for Minardi and Jaguar during the 2003 Formula 1 season.
He has driven in major US open-wheel racing since the 2004 season and was making his 174th IndyCar start in Sunday's race.
Wilson has recorded seven wins in Championship Auto Racing Teams (CART) and IndyCar races, his most recent coming at Texas in 2012.