Speed and alcohol appear to have been factors in a fatal one-vehicle crash Monday morning in Harpswell.

Cumberland County Sheriff’s deputies were called to the intersection of Reach and Mountain Roads about 7 a.m. Monday, and found a pickup truck had overturned on a dirt embankment.

The driver, 21-year-old Mason Warren, was pronounced dead at the scene. Officers believe alcohol and speed were factors in the crash. He was not wearing a seatbelt, police said.

The sheriff’s office says Warren was driving his 2002 Chevy Silverado on Mountain Road when he drifted onto the dirt shoulder, overcorrected to get back on the road, then crossed the center line and hit a dirt embankment on the opposite side of the street, flipping the truck.

First responders told police they smelled alcohol on Warren, and a witness told investigators he had been drinking before the crash, said Cumberland County Sheriff Capt. Kerry Joyce.

The sheriff’s office is still investigating the crash.