ALLAGASH, Maine — A U.S. census worker who suffered head and facial injuries Friday in an ATV accident remained in serious condition Monday at a Bangor hospital.

Rodney Thibodeau, 55, of St. Francis and his wife, who was not named, had been using four-wheelers to document camps in the Allagash, north of the St. John River and Dickey Checkpoint, according to Deborah Turcotte, spokeswoman for the state Department of Inland Fisheries and Wildlife.

At one point Thibodeau attempted to ride through a washout in a branch road off Johnson Brook Road, Turcotte said. As he maneuvered up the opposite side of the washout, Thibodeau’s Polaris ATV rolled over onto him, causing extensive injuries to his face and head, she said. Wardens said Thibodeau was not wearing a helmet when the rollover occurred.

The accident was reported to the Maine Warden Service about noon Friday. Wardens Alan Dudley and Jeff Spencer responded, Turcotte said.

Thibodeau was driven out of the woods by personal vehicle. Emergency medical personnel were summoned from a residence in Allagash, Turcotte said. An ambulance met the victim in St. Francis and took him to Northern Maine Medical Center in Fort Kent.

Thibodeau later was flown to Eastern Maine Medical Center in Bangor in a LifeFlight helicopter.

In a separate accident Sunday at the southern end of the state, two New Hampshire girls were injured in an ATV accident in Lebanon.

Authorities say a 13-year-old girl from Rochester, N.H., was driving a four-wheeler on a road in Lebanon on Sunday afternoon when the machine rolled over. Responders took her and her passenger — an 8-year-old girl from Somersworth, N.H. — to a New Hampshire hospital with injuries that were not life-threatening.

The Associated Press contributed to this report.