Stewart Swigert of Challis died Sunday night from injuries he sustained in a July 17 single-vehicle crash on Idaho Highway 75 about 25 miles east of Stanley.

The Custer County Sheriff’s Office confirmed Swigert’s death Monday morning, after it was informed by officials from St. Alphonsus Medical Center.

Swigert, 59, was driving a Ford cement truck, traveling south, when he crossed over the center line, went off the road and rolled the truck, according to the Idaho State Police. The truck stopped next to the Salmon River, but was never in the river, Custer County Sheriff’s Deputy John Haugh said.

Swigert, who was not wearing a seat belt, was ejected and landed about 30 feet from the truck, police said. He was taken by ground ambulance to the Stanley Airport and then flown by air ambulance to St. Alphonsus Medical Center in Boise.

The Challis Redi-Mix truck was loaded with seven cubic yards of pea gravel concrete and the total weight of the unit was 51,000 pounds, according to the Custer County Sheriff’s Office.

Haugh was the first law enforcement officer on the scene. He met an ICU nurse who happened to be driving on the highway when the accident occurred. Haugh is an EMT so he and the woman administered care to Swigert until Stanley Ambulance volunteers arrived. Other passersby stopped to help clear debris from the road and assist in other ways.

In addition to the ambulance crew, Stanley volunteer firefighters and state police were at the scene.

One lane of the highway was blocked for about five hours.

The crash remains under investigation by Idaho State Police officials. The truck is being examined as part of that investigation. Police don’t yet know what caused the accident.