TOPEKA, Kan. (AP) — Authorities say a Kansas father and son were injured when their car exploded.

The explosion Sunday near Topeka had such force the roof of the car was peeled back.

Authorities say Jacob Schell and his 4-year-old son, Roman, were injured in the explosion.

Jacob Schell’s brother, Alex, says the car exploded because of fireworks inside. He said the family had been celebrating the Fourth of July and the two victims were headed home when fireworks they had in the car went off.

They were flown to the University of Kansas Hospital, where their conditions were not immediately available.

The Kansas Fire Marshal is investigating.