Pyrotol was an explosive available for a time after World War I . It was reprocessed from military surplus . Usually used in combination with dynamite , it created an incendiary blast . Since it was very inexpensive , it was often used by farmers to remove tree stumps and clear ditches . The substance was known for being used to commit the Bath School bombing in 1927 and distribution of pyrotol for farm use was discontinued in 1928 due to exhaustion of the supply of surplus explosives
Bath School bombing
Bath School disaster
Pyrotol