Five people and an unborn baby died Monday evening in two separate I-15 crashes, one in Draper and one near Mona. Several others were injured.

Two teenage boys, a pregnant woman and her unborn child and one other person died in the Mona accident. The boys and the woman were riding in a sport utility vehicle carrying seven people when it rolled off I-15 near Mona in Juab County.

The two teens and the pregnant woman were ejected from the Ford Explorer along with two others when it rolled into the median.

A sixth occupant was partially ejected while the other passenger remained in the vehicle, Utah Highway Patrol trooper Cameron Roden said.

Two medical helicopters landed at the scene, but officials only used one, to transport the pregnant woman, said Santaquin Fire Chief Shane Bott.

About six agencies responded to the scene, which caused a complete closure of the southbound lanes near the accident.

Roden said three of the crash victims were in fair condition.

Investigators at the scene were not sure what caused the accident but "suspect some sort of tire failure" could have played a role, Roden said.

Identities were not released Monday because family had not yet been contacted.

A man in his 20s died Monday evening after being critically injured in a six-car accident in Draper, where officials temporary closed I-15 at 11200 South to land a medical helicopter.

The UHP reopened the northbound lanes near the accident site after the helicopter transported the man to the hospital, where he was pronounced dead.

"The man sustained serious head trauma during the crash," Roden said.

Other crash victims were taken by ambulance to the hospital with non-life-threatening injuries.

Roden said it appears the accident occurred when a truck rear-ended the victim's car.

The accident, which occurred at 5:45 p.m., backed up traffic for miles, only allowing a trickle of the rush-hour traffic through using the far right lane.

E-mail: jhancock@desnews.com