A trucker apparently choking on a soda slammed into the back of a school bus that had stopped with lights flashing Friday, seriously injuring five people.

"One of the kids that was stepping off the bus was actually ejected as the bus was hit from behind," Kenosha County Sheriff David Beth said.

Those seriously injured included the boy trying to get off the bus, two other children, the truck driver and the bus driver, Beth said.

The injuries were not believed to be life-threatening, he said, but two of the children were airlifted to Children's Hospital of Wisconsin in suburban Milwaukee.

Others on the bus had minor injuries and were taken to four area hospitals for treatment, Beth said.

There were 16 children on the bus from Wheatland Center School District, ranging from fourth to eighth graders.

The truck driver had facial lacerations and was incoherent when he first spoke with emergency personnel, said town of Salem Fire Chief Mike Slover.

He was initially expected to be airlifted, but an ambulance on scene took him away before a helicopter could arrive.

The sheriff said the man was talking to authorities later at the hospital.

"He may have been occupied inside the cab drinking a soda," the sheriff said. "He was either coughing or choking on it."

Emergency personnel arriving at the scene found children scattered in the grassy areas of the roadside. The front end of the semi was smashed in, and the bus was pushed at an angle across part of the divided four-lane highway. Neither vehicle tipped over.

"As rescue people came, they found children scattered all over the grass. Some of the children were bounced around pretty handily," Beth said.

He said investigators think the trucker did not see the bus. There were no skid marks where the accident happened about 3:40 p.m. just over a rolling ridge on state Highway 50.

"The semi came over the hill and struck the bus right in the middle of the rear end," Beth said.

School officials, local authorities and parents went to the scene as they heard of the crash.

"A lot of parents are here. They are very concerned," the sheriff said.

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