MOUNTAIN HOME -- Two people were taken to the hospital after a semi overturned on Highway 20 Monday morning.

The crash happened just before 9 a.m. between Mountain Home and Fairfield, at mile marker 124 in the Castle Rocks area.

According to the Elmore County Sheriff's Office, a woman was driving west in the semi truck when she apparently lost control. The truck crossed the center line and slammed into a concrete guardrail before rolling onto the driver's side.

The truck came to rest on the road, while the trailer rolled over the embankment, spilling its load of peat moss down the hill.

The driver was taken by air ambulance to St Luke's Regional Medical Center in Boise. A man who had been riding in the truck as a passenger was also hurt, and was taken to a local hospital by ground ambulance.

According to the Elmore County Sheriff's Office, speed is believed to be a factor in the wreck. The crash remains under investigation.

The names of the injured man and woman have not been released.

One lane of Highway 20 was blocked for several hours.