TOPSFIELD — An 18-year-old Brookton Plantation man driving to school was killed in a collision with a tractor-trailer Wednesday morning.

Dylan Porter was pronounced dead at the scene of the accident, which occurred at about 7:10 a.m. on U.S. Route 1 about two miles north of Route 6, the Washington County Sheriff’s Office reported.

Porter was driving a 2003 Ford Taurus south on U.S. 1 and was headed to school at Lee Academy when he collided with a 2010 Western Star operated by Kevin Lagase, 39, of New Denmark, New Brunswick, Canada. Lagase was not injured.

The car struck the empty logging truck in the rear of the trailer, according to Chief Deputy Shawn Donahue. The trailer was damaged, and the car was a total loss.

One of the vehicles crossed the center line, said Donahue, but investigators were not able to determine immediately which one had entered the other lane.

Route 1 was closed to traffic in both lanes for several hours following the accident.

Porter “was having a good senior year,” according to accounts by school staffers, said W. Gus LeBlanc, who is in his first year as headmaster of the private school.

Porter was active in art and photography, LeBlanc said, as well as in the automotive program at the regional technical center in Lincoln.

The headmaster described Porter, whose older sister who graduated from Lee Academy, as a person who was capable of making friends and associations with all kinds of other youths. “He crossed a lot of barriers,” LeBlanc said, and made friends with athletes, scholars, exchange students, and local students. “That’s just the kind of kid he was.”

The headmaster called a school meeting in the academy auditorium to inform students of Porter’s death after school officials were notified.

“It was a pretty sober group. … You could have heard a pin drop,” he said. Some students became upset, according to LeBlanc.

The school has a planned response for such incidents, he said, and it was put into place. Counselors were made available to students, some of whom took advantage of the opportunity. Counselors also will be available later in the week.

A school staff member was going to meet with members of Porter’s family Wednesday night, said LeBlanc. Any plans for a response by the school will depend on the family’s wishes, he said.

The crash remains under investigation, although alcohol, speed and road conditions did not appear to be factors in the accident, according to Donahue.

The sheriff’s office was assisted by members of the Maine State Police, Calais Fire and Rescue, Indian Township Fire and Rescue and Topsfield Fire Department.