Ottawa High School is closed until further notice, after a gas leak was discovered on the northeast side of Main Street.
The Ottawa Police Department informed school administrators at about 12:45 p.m., which is the same time students were being dismissed from school.
No one was allowed to enter the building or the campus until high school administrators received clearance from the Ottawa Fire Department. All games, practices and events are canceled.
The plan is for the school to reopen Tuesday as usual, said Superintendent Michael Cushing.