FORT FAIRFIELD – A Massachusetts boy was injured Saturday when the snowmobile he was driving rolled over onto him.

Camden Gaspar, 10, of Rochester, Mass., was driving an older model Yamaha snowmobile at about 5 p.m. with his grandfather Donald Gaspar, 59, of Fort Fairfield near the elder Gaspar’s home when the accident occurred.

According to Sgt. Thomas Ward of the Maine Warden Service, the snowmobile hit a piece of pipe that was frozen horizontally under the snow. The impact caused the boy to lose his balance and fall off the snowmobile. The machine then rolled over onto him.

The boy suffered a broken right kneecap, a fractured skull and facial fractures, Ward said. His grandfather was not injured.

The child was taken by Crown Ambulance to The Aroostook Medical Center in Presque Isle. His condition was not available Sunday afternoon.

Neither Camden nor Donald Gaspar were wearing helmets, according to Ward, who said Camden’s injuries would have been less severe had he been wearing head protection.

The warden urged all snowmobilers to be cautious when driving, as there is little snow to cover hidden objects. Hitting something such as a rock, piece of wood or a frozen clump of dirt hidden just under the surface of the snow could cause riders to lose their balance and be injured in an accident.

Warden Ed Christie and the Fort Fairfield Police Department investigated the accident.

Christie also investigated another snowmobile accident Saturday that occurred in Washburn at about the same time as the one in Fort Fairfield.

According to the warden, the accident occurred in the park near the mill pond in downtown Washburn. The ski of a northbound 2000 Polaris snowmobile operated by Dustin Sprague, 24, of Florida rode up onto an obstruction which caused the sled to slip into the path of a southbound 1998 Arctic Cat operated by Jerry Castunguay, 22, of Holden.

Both machines were demolished in the crash, Christie said. The snowmobile operated by Sprague had been rented from Earl’s Snowsleds and Sales in Caribou.

Sprague and Castunguay were not injured. Isabel Herevia, 25, of Florida, a passenger on Sprague’s snowmobile, suffered minor injures, but refused treatment.

All of the riders were wearing helmets, the warden said.

Officer Scott Fitzgerald of the Washburn Police Department investigated the crash.