NORMAL - A preschool boy was left alone on a Unit 5 school bus for half an hour Wednesday afternoon until he was discovered by an employee inspecting the bus.

"This kind of situation is completely unacceptable and we are taking appropriate steps to do the best we can to make sure this never happens again," Unit 5 Superintendent Gary Niehaus said in a statement."The Unit 5 superintendent's office has spoken with the boy's family and expressed our deep regret this situation occurred."

An early childhood education student was left on a parked school bus about 1 p.m. Wednesday at the transportation garage on Eagle Road on Normal's north edge.

The boy boarded the bus at his home to attend afternoon classes, and did not get off the bus when it arrived at the school. Whether anyone at the school noticed that he did not arrive was not released by district officials Thursday.

The bus returned to the garage, where it was parked. The driver and a monitor who rides with the driver on the route got off the bus.

About 30 minutes later, an employee who routinely inspects each of the buses discovered the boy, who then was returned home, school officials said.

The boy, who is under 5 years old, was awake when he was found, said spokeswoman Dayna Brown. "No one is certain why he didn't get off the bus," she said.

The Normal-based district has procedures intended to prevent this from happening, and those procedures were not followed, Niehaus said.

At the end of every bus route, the driver and monitor are required to search the bus to ensure no students are left behind. "That did not happen," Niehaus said.

The bus driver and bus monitor are suspended pending the outcome of an ongoing investigation by the district.

"It was a follow-up procedure to check each of the buses that caught the problem, and fortunately it did not go on for longer," Niehaus said. "We reiterated the proper procedures with each of our drivers today to ensure nothing like this happens again."

The district declined to release the exact age of the child or the school the boy attended for his privacy, Brown said.

On the first day of school in Unit 5, a boy got on the wrong school bus, so he wasn't at Glenn Elementary School when his mother tried to pick him up in his classroom.

Another Unit 5 boy was dropped off at home alone instead of at his assigned after-school site on the first day of school. Niehaus met with the child's mother and the teachers to ensure that would not happen again. At the time, he also called it a "scary" situation.

In Bloomington District 87, Superintendent Bob Nielsen said there have been no children left on a bus to the best of his knowledge. However, students have gotten on the wrong bus or gotten off a bus with a friend without a parent's immediate knowledge this year, he said.