The worst school massacre in American history wasn’t a college campus. Bath School in Bath, Michigan was destroyed via explosives in 1929, leaving 38 dead at the scene. Six more deaths, including the suicide of the perpetrator, were related to the incident.
Actually Bath was worse
The Bath School disaster was a series of bombings in Bath Township, Michigan, USA, on May 18, 1927, which killed 45 people and injured 58. Most of the victims were children in second to sixth grades attending the Bath Consolidated School. The bombings constituted the deadliest act of mass murder in a school in U.S. history.