The Macomb County Sheriffs Office said two adults and two kids were on a boat when it exploded in Harrison Township on Sunday afternoon.
Officials say the four people were anchored in Belvedere Bay, and when they attempted to leave, the engine compartment caught fire and exploded.
The four people were ejected from the boat, the sheriffs office says.
According to the sheriffs office, a nearby boater was able to help get the occupants out of the water; three of the four people were injured in the incident and transported for medical treatment.
Officials say the three injured people are stable at this time.
No foul play is suspected in the incident.