BRADFORD – A Massachusetts man was critically injured Monday after losing control of a snowmobile in a field and rolling over several times.

William Legare, 56, wasn’t wearing a helmet at the time of the accident and suffered a brain injury, a state warden said he was told Monday afternoon by staff at Eastern Maine Medical Center. Legare remained unconscious at EMMC hours after the accident, Warden David Georgia said, although a hospital nursing supervisor said she had no information about the Massachusetts man.

Legare was riding lead in a group of four. Behind him were three youths 15 years old or younger, including Legare’s grandson, said Georgia, who with Warden Mike Morrison investigated the accident. The three youths were wearing helmets.

The four had just crossed the West Road in Bradford at about 1 p.m. when one of the youths stopped short in a field and was rear-ended by another, Georgia said. The impact caused no injuries but broke a taillight on a sled.

The youths told wardens that Legare acted as if he were disgusted with them and jumped on his sled and rapidly accelerated.

The field was wind-swept, Georgia said, and there were some bare patches and ice. Legare didn’t get very far before hitting one of the icy spots, and the snowmobile spun around and rolled over three or four times, the wardens reported.

The 15-year-old went for help on his snowmobile but crashed into some trees near a residence where the teenager could not get anyone to come to the door. The teenager pulled his sled from the snow and trees and, unable to flag others down, headed to a nearby convenience store.

Legare was taken by ambulance to EMMC.

The accident is still under investigation, Georgia said.