Both incidents were reported in the past month in the Christina School District.
Both students were reportedly being transported to Christina Early Education Center.
Back on January 27th, one child was left by themselves for about an hour.
Then on Wednesday another child was left alone for four hours.
School officials say the buses are supposed to be checked at the end of each route, but clearly policies were not followed.
Two drivers and two aides involved in the incidents are on leave as an investigation continues.