Everything about Bloomberg is exaggerated, including his girth.
In terms of casualties no US school shooting has ever come close to the 1927 Bath, MI school bombing. 45 people, including 38 school kids, were killed when demented Andrew Kehoe; a school board member, bombed the school. Kehoe planted two bombs under the school building: One failed to detonate.
Guess what? School shootings are not new in the USA. A history of US school shootings. Including this one:
February 26, 1902 Camargo, Illinois teacher Fletcher R. Barnett shot and killed another teacher, Eva C. Wiseman, in front of her class at a school near Camargo, Illinois. After shooting at a pupil who came to help Miss Wiseman and wounding himself in a failed suicide attempt he waited in the classroom until a group of farmers came to lynch him. He then ran out of the school building, grabbed a shotgun from one of the farmers and shot himself, before running away and leaping into a well where he finally drowned. The incident was likely sparked by Wiseman's refusal to marry Barnett.