Anibal "Bebo" Santos was taken to Marlborough Hospital where he was pronounced dead, according to Marlborough Police Chief Mark Leonard.
Police received a call at 2:15 a.m. from a passerby.
Officers arrived and found Santos had failed to negotiate the turn and had struck a tree, police said.
"There is a curve in the road right where the accident occurred," Leonard said.
There were no other occupants in the truck, and police believe no other vehicles were involved, Leonard said.
Marlborough firefighters used the Jaws of Life to remove Santos from the vehicle. He was not conscious when rescue crews arrived, Leonard said. Life Flight was called in, but Santos was taken by ambulance to Marlborough Hospital, Leonard said.
Police are investigating whether alcohol or speed were involved, as well as if Santos may have fallen asleep.
"That is certainly something we'll try to determine," Leonard said referring to the exact cause of the accident. Santos was not wearing a seat belt, Leonard said.
Marlborough Police and the state police accident reconstruction unit are investigating.
Santos had been on the Newton Fire Department for almost four years and was a dedicated firefighter, according to Lt. Alan Leone.
"He was a very nice guy," Leone said. "Since joining the department Anibal had gone out and become a certified EMT, and in the state he's a certified hazmat technician."
Santos worked part time at Home Depot and was nearly finished with an associate's degree in fire science technology from Middlesex Community College, Leone said.
"He was very dedicated and very interested in the job," Leone said. "Most of the guys who knew him liked him. He will definitely be missed."
Newton Fire Chief Joseph LaCroix, also a Marlborough resident, responded to the scene after hearing what happened, Leone said.
Newton's Fire Department as well as several others are working on having a service for Santos, Leone said.
He had relatives on the Lowell and Waltham fire departments. Leone said Marlborough Fire Department will also most likely be involved.
"There is a lot of camaraderie," Leone said. "Although they might not have worked with him, it is tough to see one of your own involved in an accident like this. These guys take it to heart."
Calling hours are Tuesday, from 1 to 4 and 6 to 9 p.m., at the Sullivan-Fitzgerald & Collins Funeral Home at 378 Lincoln St. in Marlborough.
