On June 5, 1942, the Herald-News in Joliet reported on one of the deadliest industrial accidents in state history: the explosion at the Elwood Ordnance Plant. At 2:41 a.m., an explosion took place in a loading line at a plant Building 10. Workers had been loading anti-tank pressure minds into railroad cars. Whatever happened next set off three railroad cars loaded with the weapons, an explosive weight equal to approximately 62,600 lbs. of TNT. The blast shattered windows for miles around and was allegedly heard in Waukegan, close to 100 miles away. The 48 killed made it the deadliest US ammunition plant incident of World War II.

The EOP, along with a sister facility in Kankakee, had a reputation as the world’s most advanced weapons production plant. The twin factories came about two years earlier when the US government bought up over 36,000 acres of local farmland. At their peak, the facilities employed over 10,000 workers making bombs, shells, mines, detonators, a billion pounds of TNT (at Kankakee), and other hardware.

The EOP represented one small part of the United States’s awe-inspiring industrial ramp-up to fighting a world war. In 1939, when Germany invaded Poland, the US had virtually no large-scale weapons manufacturing. Hopes to convert existing industries to weapons faltered due to the specific needs—in terms of equipment, techniques, and training—related to munitions. The government opened a network of sixty-some facilities over the new few years. After the war, the Elwood and Kankakee plants lived on as the Joliet Arsenal. Production of munitions ceased after World War II, then picked up again for the Korean War. The Elwood side also manufactured weapons in the early years of the Vietnam War.

In 2001, private donations and state money paid for a memorial to those killed in the 1942 accident.