The Emergence of the Indiana Army Ammunition Plant: A Chronicle of Wartime Necessity

The advent of the Indiana Army Ammunition Plant was inevitable because of the looming tempest of global conflict. Spurred by the National Defense Appropriations Act and the subsequent Munitions Program, the United States Ordinance Department enlisted private corporations to undertake the formidable task of designing and constructing munitions factories for the production of smokeless gunpowder and other ordinances.

Speculation abounded regarding the selection of the Indiana site to host one of these critical facilities. In July 1940, this esteemed publication announced that the world’s largest smokeless powder plant would rise upon the grounds of pioneer cemeteries, historic residences, homesteads, churches, and the former Rose Island Amusement Park, met with remarkably little resistance from those displaced. The landowners accepted the loss of their properties as an unfortunate yet necessary sacrifice in the face of impending war.

The mammoth endeavor, encompassing 1,401 structures across 9,790 acres, would become the largest plant under the command of the Industrial Operations Command, though the final tally would far surpass this initial figure. Constructed upon 19,200 acres, the Indiana Army Ammunition Plant (IAAP) comprised the Indiana Ordnance Works Plant 1 (IOW1), tasked with smokeless powder production, the Hoosier Ordnance Plant (HOP), colloquially referred to as the “bag plant,” and the Indiana Ordnance Works Plant 2 (IOW2), known as the “rocket plant.”

Construction commenced on August 26, 1940, under the stewardship of E.I. du Pont de Nemours & Co. Within three months, over 10,000 workers had been employed in the erection of IOW1. At the zenith of construction in May 1941, a staggering 27,520 workers labored tirelessly to bring the plant to fruition, culminating in completing IOW1 in May 1942.

IOW1 contained 800 buildings that were divided into four main areas. The administration area included a main administration building, telephone exchange, hospital, repair shop, cafeteria, guard headquarters, and office space. The smokeless powder manufacturing area included six parallel, nearly identical manufacturing lines, including two power plants, blending towers, two Ammonium Oxidation plants, and two Nitric and Sulfuric Acid Concentration plants. Further south was the storage and shipping area that included approximately 100 above-ground magazines, road ship houses, and road storage and shipping houses. Towards the Ohio River was River Ridge, a collection of 19 two-story, wood-frame houses.

On January 10, 1941, construction began on the Hoosier Ordnance Plant (HOP) and was partially in operation by September; construction was finished on February 2, 1942. The load, assembly, and pack facility prepared cannon, artillery, and mortar projectiles and integrated five distinct areas. The administration area included a main administration building, a main change house, and a hospital, and the production, maintenance, and storage area contained a bag manufacturing building, an inert stores warehouse, a repair shop, a fire station, and a heating plant. A charging area contained 8 load lines for bag-loading smokeless powder and 4 igniter lines for bag-loading black powder. In contrast, the powder magazine area contained 177 earth-covered, steel-reinforced concrete igloos. At River Ridge, an additional 17 two-story wood-frame houses were constructed.

Construction on Indiana Ordnance Works Plant 2 (IOW2), a rocket propellant plant, did not begin until late 1944. Although production did take place for approximately five weeks, the plant was never completed before Japan’s surrender in August 1945. Construction stopped on August 13.

The Indiana Army Ammunition Plant contained 19,200 acres, 1,700 buildings, 84 miles of railroad track, 190 miles of road, and 30 miles of fence and cost $133.4 million to complete.

IOW1 began producing smokeless and black powder for HOP and other load, assembly, and pack operations on April 11, 1941. Single-base smokeless powder was used as a propellant for a projectile, while black powder was used to ignite the smokeless powder. By July, IOW1 had produced twice as much powder as the nation had the previous year.

The Indiana Army Ammunition Plant, a testament to the unwavering resolve and industrial might of the nation in times of crisis, stood as a crucial bulwark against the encroaching forces that threatened the very foundations of liberty and democracy.