School bus accident in Mississippi: a school bus driver killed and eight students injured today in an accident on the Mississippi Expressway in Benton County

A Mississippi school bus driver died when his bus went out of a highway Tuesday morning and rolled into a ditch, officials said. Four students injured in the accident were listed in a serious but non-critical condition in a Tennessee hospital.

The bus came out of the 72 freeway and overturned several times, said Mississippi Road Patrol captain Johnny Poulos at CBS News. No other vehicle was involved in the crash.

The bus was carrying students to the Benton County School District. Superintendent Steve Bostick identified the pilot of CBS WREG-TV's subsidiary as Chester Cole.

Cole apparently had suffered a heart attack, which led him to leave the road, Bostick told WREG-TV. Cole was at the beginning of his bus line when the accident occurred.

Bus students were aged 7 to 13, Bostick told the station. Eight children were transported to the Memphis Bliss Children's Hospital in Tennessee for treatment.

At a press conference, Dr. Regan Williams, medical director of trauma at the hospital, said four children were in serious but uncritical condition and needed to be admitted. She said that she could not describe their injuries but felt their recovery time between one and ten days.

The other four children had minor injuries and had to return home Tuesday, Williams said. Benton County is located along the Mississippi-Tennessee border, about 50 miles from Memphis.