KNOX, Maine — Two days after James “Jimmy” Curtis, 39, was killed in a head-on collision on Interstate 95, his stunned co-workers put a padlock on his locker at the Cianbro fabrication shop in Pittsfield.

“We retired his locker today,” Craig Chambers, the shop foreman, said Tuesday morning of his longtime employee. “It is devastating to us and all his other team members who have worked with him over the years. He was a giver, not a taker. He took care of his mom and dad, he liked puttering around on the farm and liked to find used tractors to buy. Jimmy was a simple man. He’d give the shirt off his back to help someone else. I can’t say enough good about him.”

The Maine State Police said that Curtis was killed instantly after Richard Holden, 55, of Carmel, who was driving his SUV north in the southbound lanes, collided with Curtis’ pickup truck. Holden’s license had been suspended in both Maine and Maryland, and police are investigating whether drugs or alcohol played a role in the collision.

Co-workers and a former teacher remembered Curtis as a kind person and hard worker who had a memorably keen sense of humor. He started working at Cianbro at 20, just after he finished welding school, and while it took him some time to loosen up, eventually he did, Chambers said.

“He started playing pranks, like filling hard hats with water,” the foreman said. “Nothing that would jeopardize anybody’s safety. He was a big teddy bear.”

Tanya Hubbard, who taught English at Mount View High School in Thorndike for 37 years, remembered Curtis, who graduated in 1992.

“He was just a very kind young man. He was very polite. I used to call him one of my boys,” she said. “The senselessness of this is just devastating.”

Hubbard said “her boys” were the ones who might have been a little rough around the edges, but who had hearts of gold, and Curtis fit that bill.

“The kind of guy who would stop and help you change your tires, no questions asked,” she said.

Jurgen Bell, the Cianbro fabrication shop superintendent, said that he hired Curtis and watched him learn and grow on the job.

“He would have retired here,” Bell said. “The last time I saw Jimmy was Saturday night, and the accident happened Sunday. I heard a bad accident happened. My co-worker called me up on the phone and told me it was Jim. I just couldn’t believe it. You ask yourself why? How come? You just don’t know.”

Curtis, he said, will never be forgotten at Cianbro, where he was part of a tight-knit team and would work days, nights or weekends — whenever he was needed. Most recently, he’d worked the night shift, which supervisors canceled on Monday.

“I wanted to give the crew an extra day to think, and to let the healing begin,” Bell said. “It’s a big family at work. You come to work to have fun. That’s what we strive for. Jimmy fit right in.”

When he wasn’t working, Curtis spent time with his parents, James and Shirley Curtis of Knox, and other family members. He loved snowmobiling, going to Hollywood Slots in Bangor, helping his father grow and sell beans on their farm and more. He’ll be missed, friends said.

“He was just a good, happy-go-lucky farm-type boy. A hard worker. He gave his all, and didn’t ask for much in return,” Bell said. “It’s a shock.”