WATERVILLE, Maine — The driver of a car that struck the rear end of a horse-drawn wagon on the Industrial Road on Christmas Day and injured seven people may have been blinded by the afternoon sun, Waterville police said in a news release issued Saturday.

One woman remained in critical condition at a Portland hospital, where she was taken by Lifeflight after the accident. Kathy Marciarille, 56, of Rome apparently fell off the wagon and was struck and then run over by the car, Deputy Chief Charles Rumsey wrote in the news release.

Rumsey said the driver, Richard Libby, 73, of Clinton, was not injured in the crash. Libby, who was alone in a gray 2016 Chrysler 200 sedan, had been traveling west on the Industrial Road in Waterville when he overtook the horse-drawn wagon.

“It appears that Libby’s vision was impaired by the angle and intensity of the afternoon sun, and he did not see the carriage before striking it with his vehicle,” the news release stated.

The wagon was driven by Cathleen Simmons, 42, of Sidney and was owned by S&S Carriage Rides, also of Sidney. Police wrote that the force of the impact was so severe that Simmons’ seat broke. The two horses pulling the wagon were not injured in the accident. Simmons’ company was providing rides to guests and volunteers from a Christmas dinner hosted at the Waterville Elks Lodge, Rumsey wrote.

Many fire, police and other emergency medical units arrived at the scene to provide assistance and to begin the investigation, he said.

Wagon passengers Maria Hyatt, 55, of Arundel; Joseph Hyatt, 59, of Arundel; Kimberly Knox Lawrence, 53, of Albion; Stacey Hachey, 53, of Winslow; Andrew Giroux, 41, of Winslow; and Marty Baird, 46, of Massachusetts, suffered minor injuries in the crash.

Simmons, the driver, and passengers Brenda Blair, 59, of Clinton; Norman Lawrence, 64, of Albion; Krislyn Hyatt, 26, of Arundel; Tammy Giroux, 44, of Oakland; Sophia Giroux, 4, of Oakland; Andrew Giroux, 2, of Oakland; and Jeanette Deluca, 85, of Commack, New York, were not injured in the crash.

The crash is being investigated by the Waterville Police Department with assistance from the Maine State Police, the Fairfield police and the Maine state fire marshal’s office. After the crash, both drivers were taken to local hospitals, where their blood was drawn for testing, which is common practice in a crash where serious injury has occurred.

“Based on the preliminary state of this investigation, it appears that neither speed nor alcohol were a factor,” the police report stated.

Libby’s car was towed by Ace Towing to that company’s facility, where it will be inspected for mechanical defects and for evidence gathering and analysis, Rumsey wrote.

The Maine state fire marshal’s office will share information gleaned from the crash with a legislative study committee that is considering how best to ensure safety for carriage rides, police said, adding that a final conclusion on the cause of the crash is not expected for some time because of the complicated nature of the reconstruction investigation.

Any decision about potential charges resulting from the crash will be made by the Waterville Police Department after the investigation is completed, Rumsey said.