The T. A. Gillespie Company Shell Loading Plant explosion, sometimes called the Morgan Depot Explosion, occurred at 7:30 p.m. on October 4, 1918 at an ammunition plant operated by the T. A. Gillespie Company and located in the Morgan area of Sayreville in Middlesex County, New Jersey. The initial explosion triggered a fire and subsequent series of explosions which continued for three days. The facility, said to be one of the largest in the world at the time, was destroyed along with more than 300 buildings, forcing reconstruction of South Amboy and Sayreville.