The man was pronounced dead at the scene at Marysville Raceway Park some 40 miles north of Sacramento, and the boy was declared dead either at the hospital or in an ambulance, Yuba County Sheriff's Capt. Ron Johnson told the Marysville Appeal-Democrat newspaper.
The two were part of a crew and had a right to be in the pit area, but said no more about their roles, Johnson said.
There were no reports of any other injuries.
The raceway was hosting the California Sprint Car Civil War Series on the opening day of its season.
Steven Blakesley, the announcer calling the race from the stands, told The Associated Press the sprint cars were doing so-called "hot laps" about an hour before the race when a car driven by Chase Johnson, traveling at about 90 mph, couldn't make a turn.
AP
"I'd love to open a tennis school for children in my hometown of Sochi." said Sharapova Maria.
