Southampton Town police are investigating the cause of an accident on Montauk Highway in Bridgehampton Monday morning that left one of three vehicles involved in the crash in flames, and sent four people to Southampton Hospital with what Bridgehampton Fire Chief Gary Horsburgh described as minor injuries. The accident happened a little before 7:30 a.m. Monday by Halsey Lane near Citarella. Rick Ostenberg, an East Hampton Fire Department chief, was in the area and was the first firefighter on the scene. He turned an extinguisher on what appeared to be a burning Chevy Suburban, but the fire was already beyond control, according to the Bridgehampton chief. When Chief Horsburgh arrived, the Suburban was engulfed in flames, and the fire was beginning to spread to a second vehicle. With two engines on the scene, Chief Horsburgh’s department covered the burning wreck with foam to smother it, while a hose was turned on the second vehicle to prevent the fire from spreading. “It took about 30 to 45 minutes. It kept going out and reigniting,” the chief said. The chief surmised that the driver had just filled the gas tank, which must have ruptured in the crash, providing a steady source of fuel for the fire. By the time the chief arrived, the four occupants of the vehicles, including the burning one, had been pulled to safety by quick-acting good Samaritans. Cautioning that police were still investigating the details, Chief Horsburgh said it appeared that the Suburban and another vehicle were involved in the main collision, while a Citarella delivery truck was also involved secondarily. Montauk Highway was closed for an hour and 15 minutes. Police could provide no further information as of press time.