A Fillmore teenager and a Tooele County man were killed and another youth critically injured in two separate traffic accidents Sunday on Utah highways.

Killed in the accidents were:Paul Troy Baker, 16, of Fillmore.

Monte S. St. Clair, 35, Lake Point, Tooele County.

Baker was driving southbound on I-15 just south of Scipio when the pickup he was driving went off of the road for an unknown reason, the Utah Highway Patrol reported. The truck rolled four and a half times and ejected Baker and passenger Alan Stephenson, 15, also from Fillmore.

Stephenson was in critical condition Tuesday at LDS Hospital, a spokeswoman said. Neither youth was wearing a seat belt in the accident. The cause of the accident is still under investigation, but troopers said no alcohol was involved.

St. Clair was driving southbound on U-36 near Erda, Tooele County, when his vehicle went off to the right side of the road about 3:50 p.m. UHP Sgt. Ron Ostler said St. Clair overcorrected the vehicle and then rolled. He was not wearing a seat belt and was ejected from the vehicle.

St. Clair was taken to Tooele Valley Hospital, where he was pronounced dead on arrival. "He'd have survived if he'd had his seat belt on," he said.