Question: The explosive substance used by Andrew Kehoe was discontinued for farm use in what year?
Sentence (from "Bath School disaster"): The Bath School disaster, sometimes known as the Bath School massacre, was a series of violent attacks perpetrated by Andrew Kehoe on May 18, 1927 in Bath Township, Michigan, which killed 38 elementary schoolchildren and 6 adults and injured at least 58 other people.
Relevant evidence: Yes