Two people were killed Saturday night at Marysville (Calif.) Raceway Park after a sprint car sped over a wall and into the pit area, the Sacramento Bee reported.
A 68-year old man died on the scene and a 14-year-old later died at a hospital, according to the Yuba County Sheriff's Department.
The names of victims were not released.
Track announcer Steven Blakesley told ABC News that the 14-year-old was the driver's cousin and the other victim was the owner of several race cars.
Marysville track promoter Paul Hawes said that the two victims were part of the driver's family and crew.
The driver, 17-year-old Chase Johnson, was uninjured.
The crash occurred about 6 p.m. PT during warmup laps for the first race of this year's California Sprint Car Civil War Series. The race was canceled.
It was not clear what caused the accident but Blakesley speculated that Johnson may have had mechanical problems because the car did not slow down as it lost control in the first turn, went over a retaining wall and slid about 100 feet before hitting the victims.
There were no other injuries reported.