(CNN) -- One child died and several were injured Friday in Bolivar County, Mississippi, when a school bus collided with a tractor-trailer on a foggy stretch of road, officials said.
The bus was carrying elementary-school and high-school students when the accident happened around 7 a.m. Friday, said Cedrick Ellis, superintendent of the Shaw School District, in Shaw, Mississippi.
A "younger child" was killed in the accident, said Dr. J.O. Trice, a deputy county coroner.
Ellis said the bus and a tractor-trailer loaded with gravel collided, causing both vehicles to overturn.
The Mississippi Highway Safety Patrol is investigating, Ellis said. It was not clear if the fog contributed to the crash,.
CNN's Maria White and Vivian Kuo contributed to this report.