Over 100 people were attending the Fireball Derby, a Sprint C-Main event at Avalon Raceway, when a car’s wheels detached and flew into the crowd about 9pm on Friday.
The tyre struck a volunteer who was standing in the crowd.
The person was treated at the scene by aid crews.
Another person was hit but did not require treatment.
Social media vision shows the tyre coming loose from the car before it soared through the barrier and into the crowd.
Avalon Raceway management said the tyre and wheel both disconnected due to a part failure.
A review into track procedures is now under way.
