Indiana Army Ammunition Plant

Indiana Army Ammunition Plant

The Indiana Army Ammunition Plant (INAAP) is a former military ammunition and ordinance factory in Charlestown, Indiana. It was the largest gunpowder and ordinance facility of its type in the United States. INAAP was constructed after the passage of the first National Defense Appropriations Act. Four days after the enactment of the Act, the Munitions Program was passed in which the U.S. Ordinance Department sponsored private manufacturing corporations to design and produce ammunition factories, producing smokeless gunpowder and other ordinances.


The development of the Indiana Army Ammunition Plant (INAAP) was mired in speculation during the lead up to World War II. Rumors of the plant’s construction began to spread when C.V. Artwell, a real estate operator from Delaware, began taking options on large tracts of land between Charlestown and the Ohio River. 30 The rumors proved true as in July 1940, the Courier-Journal newspaper announced that the world’s largest smokeless powder plant would be built near Charlestown. 1 It would be the largest facility in the Industrial Operations Command and contain 1,401 structures over 19,200 acres 1 10 11 costing $50 million to erect. 30

Within months, 13,000 workers from across the country descended upon the small town. 30 Street corner markets popped up, schools overflowed with new students, and rental prices for rooms became astronomically high. Rooms in town were rented per shift for sleeping purposes, and garages and chicken huts were converted into makeshift bedrooms. Seventeen mobile home parks were built that contained more units than Charlestown’s 250 homes. The post office went from one clerk to nine to handle the 300% increase in mail volume and surging money order requests that were related to INAAP’s $400,000 per week payroll.

A construction contract for the government-owned, contractor-operated smokeless powder plant was let to the E.I. du Pont de Nemours Company (DuPont). 10 The Quartermaster Corps would oversee work. The smokeless powder plant was one of three separate manufacturing facilities planned at INAAP which included Indiana Ordnance Works Plant 1 (IOW1) for smokeless powder, Hoosier Ordnance Plant (HOP) for bagging powder, and Indiana Ordnance Works Plant 2 (IOW2). 10 11 The three facilities were consolidated into the Indiana Arsenal on November 30, 1945, as designated under the WD Circular No. 329. 9 11

Construction on IOW1 began on August 26, 1940, 11 and by November, duPont had over 10,000 laborers on site. 10 At the height of construction in May 1941, there were 27,520 workers employed. IOW1 was completed in May 1942 at the cost of $74,956,394 11 and contained 800 buildings divided into four areas: 9 10 11

  • Administration: Included an administration building, telephone exchange, hospital, repair shop, cafeteria, and guard headquarters.
  • Smokeless Powder Manufacturing Area: Included six parallel, nearly identical manufacturing lines with two ammonium oxidation plants, two nitrocellulose manufacturing and purification areas, two nitric and sulfuric acid concentration plants, and two propellant manufacturing and finishing areas. Major support areas included an aniline manufacturing area, two coal-fired power plants with 68,750 KVA turbogenerators, and 450 above-ground storage tanks.
  • Storage and Shipping Area: Included 100 above ground magazines, and storage and shipping houses.
  • River Ridge: A residential neighborhood for high ranking officials that included 17 two-story wood-frame houses, and amenities such as a baseball diamond, basketball court, community center, horseshoe pits, playgrounds, a swimming pool, and volleyball court.

Construction on HOP began on January 10, 1941, 11 was partially in operation by September 10 and finished on February 2, 1942, at the cost of $27,851,660 11 by Winston Brothers, C.F. Haglin & Sons, Missouri Valley Bridge & Iron, and Sollitt Construction. The load, assembly, and pack facility was used to prepare cannon, artillery, and mortar projectiles and had five distinct areas: 9 10

  • Administration: Included an administration building, change house, and hospital. The hospital (Building 719) served as a hospital and laboratory and included male and female wards, a laboratory, X-Ray equipment, and a whirlpool. 9 (It later became Employment Building 2601, and a laboratory from 1987 to 1990.)
  • Production, Maintenance, and Storage Area: Included a bag manufacturing building, an inert stores warehouse, a repair shop, a fire station, and a heating plant.
  • Charging Area: Included eight load lines for bag loading smokeless powder and four igniter lines for bag loading black powder.
  • Powder Magazine Area: Included 177 earth-covered, steel-reinforced concrete igloos.
  • River Ridge: The addition of 17 two-story wood-frame houses.

Construction on IOW2, a rocket propellant plant, did not begin until December 8, 1944. 11 Although sub-production did take place for over five weeks, the facility was never completed before the surrender of Japan in August 1945; 10 construction stopped on August 13. 11

In total, there were 1,700 buildings at IOW1, HOP, and IOW2 that were completed over 19,200 acres at the cost of $133.4 million. 10 30 Broken down, it included 34 administrative buildings with 186,583 square feet; 2 hospitals; 576 production buildings with 2,052,521 square feet; 3 research and design buildings at 3,992 square feet; 114 standard magazines at 299,311 square feet; 21 utility buildings at 279,681 square feet; 176 igloos at 646,887 square feet; 149 warehouses at 617,019 square feet; and 566 miscellaneous structures at 3,302,029 square feet.

INAAP featured 30 miles of fence, 84 miles of railroad track equally served by the Baltimore & Ohio and Pennsylvania Railroads, three railroad yards (Bethany that could hold 60 cars with explosive materials in HOW; Ridley that could hold 425 cars in IOW1; and Watson that could hold 200 cars with inert materials in HOW), and 190 miles of roadway, 5 miles of which were unpaved. INAAP was also served by several sanitary surge disposal units that could handle nearly 1.5 million gallons per day, and numerous deepwater wells along the Ohio River that could supply the site with 50,200 gallons per minute.

Due to the presence of black powder and other highly volatile materials, safety was one of the utmost concerns at INAAP. Buildings were spread far from one another to diminish the chance of a mass explosion, and copper-lined transfer chutes were utilized that reduced airborne powder movement. 10 Emergency slides were installed in some buildings to provide a quick escape. Conductive shoes were issued for workers to reduce static electricity, and employees were searched daily for matches and other hazardous materials.

Initial Production

IOW1 began producing smokeless powder and black powder for HOP and other load, assembly, and pack operations on April 11, 1941. 10 11 Single-base smokeless powder, or nitrocellulose, 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 entire nation had in 1940. 10 30

Production at IOW1 ceased on September 7, 1945. 11

Peak employment at IOW1 included 27,250 contractors and 366 government officials by May 1941. 11

HOP began operations on September 2, 1941. 30 It included weighing smokeless powder, placing it into a bag, and sewing it shut. Each charge consisted of up to seven bags of powder secured together. The increments were placed in an outer charge bag and then packed in containers and shipped or warehoused.

Nitrocellulose from IOW1 was loaded into bags made at HOP. 30 The hallmark product was a 16-inch diameter bag of powder that when loaded six deep in the breach of a battleship’s turret, could propel a 2,750-pound bullet 25 miles.

HOP employed 8,902 contractors and 87 government officials by March 20, 1945, which rapidly shrank by the time production ceased on August 18. 11

IOW2 operated between July 20, 1945, and August 31. 11 The facility was designed to manufacture double-base rocket powder which was unlike single-base in that it consisted of a 60 to 40 ratio of nitrocellulose and nitroglycerin and was used to power bazookas and other rocket-based weapons. IOW2 produced 292,700 lbs. of rocket powder during its short operation. 10

Employment at IOW2 peaked at 17,585 contractors and 36 government officials by June 1945. IOW2 was placed into standby status on February 11, 1946, and never reactivated. 11

At IOW1, approximately 25% of the employees were women while at HOP, women comprised 65% of the workforce. 10 Approximately 10% of INAAP workers were also Black, although segregation was in effect and Black people were not given office positions. German prisoners of war were used as unskilled labor and housed in barracks near IOW2. The first prisoners-of-war arrived in May 1945 but were repatriated just three months later as World War II ended. 10

Post-World War II

Between June 24, 1946, and March 31, 1950, DuPont reused IOW1 to produce an ammonium nitrate aqueous solution for agricultural purposes under a CPFF contract. Employment peaked at 156 workers in February 1947, and production peaked at 20,241 tons of ammonium in August 1949. 11

At IOW2, 44 above-ground magazines were used for propellant storage from January 1946 to August 1952. 11

Korean War

INAAP was partially reactivated in 1948 because of warfare activities relating to the Korean War. 1 10 HOW was reactivated by Goodyear Engineering on September 17, 1951, followed by IOW1 by DuPont on April 28, 1952. 11 Employment peaked with 8,067 employees by August 1953. During the war, 50 new storage and maintenance buildings were constructed on-site.

Production at HOW ceased on September 20, 1957, followed by IOW1 on September 30. 11 INAAP was placed into standby status, and Goodyear and DuPont were listed as the caretakers of the complex until 1959 when it was taken over by the Liberty Powder Defense Corporation, a subsidiary of the Olin Mathieson Chemical. 1 10

Vietnam War

On November 1, 1960, 11 Liberty Powder Defense reactivated HOW’s bag manufacturing line to produce cloth bags for 105mm artillery charges for the Vietnam War effort. 10 Olin Mathieson dissolved Liberty Powder in January 1961 and took over direct control of the plant’s operations which coincided with the reactivation of the HOW igniter and propellant loading lines which were supplied black powder and smokeless powder from other ammunition factories.

INAAP was not officially reactivated until August 23, 1961, 11 and was designated the Indiana Ordnance Plant by DAGO No. 40 on November 1. On August 1, 1963, the facility was re-designated as the Indiana Army Ammunition Plant by DAGO No. 35. 9 11

In 1966, Igloo 5185 was destroyed in an unplanned explosion, the only one to ever occur at INAAP. 9 With demand accelerating, Olin reactivated part of IOW1’s smokeless powder manufacturing lines in 1969, and employment peaked at INAAP with 11,492 workers by August 1970. 11 In February 1971, work wrapped up on the installation of electrostatic precipitators to remove dust, ash, and other participles in smokestack emissions at the power plants and on the replacement of the Ammonia Oxidation Plant with a pollution-free facility. 14 It removed a source of nitrogen oxide fumes that produced a yellowish cloud over the plant at times.

Olin continued to manage INAAP until 1972, when ICI America, a subsidiary of Imperial Chemical Industries, took control. 10

Cold War

The federal government began a modernization project of its ammunition manufacturing facilities after the United States withdrew from Vietnam. 10 ICI America began construction of three new facilities at INAAP, including a fully automated black powder production plant in an attempt to limit personnel exposure to black powder, reduce costs, and lower workforce numbers.

Construction of the Black Powder Manufacturing Facility (INAAP-074) began by Sante Fe Engineering in December 1974 with ICI America completing process equipment sub-contracts. 18 The new 30-acre, $40 million facility 10 was completed in December 1978 10 18 which included a raw materials building, a process building, four glaze houses, a screen house, and a packhouse. Several auxiliary buildings were built including a boiler house, a maintenance shop, and a change house. The plant had the capacity to produce 500,000 pounds of black powder per month 16 and could be operated by remote control using state-of-the-art technology and computerized systems with only ten employees. 18

Two separate but integral buildings were also on site. The Black Powder Sanitary Sewage Treatment Plant (INAAP-014) was constructed in 1977, 9 and featured a rapid mix chamber, flocculation chamber, settling chamber, filter sludge holding tank, final aeration, and chlorination. It was rarely used. The Black Powder Industrial Wastewater Treatment Plant (INAAP-015) was also constructed in 1977 and was non-operational for its lifespan. 9

Debugging occurring throughout 1979 9 led to the determination that additional engineering was required to correct major problems in the black powder fines recycling system, electrical grid grounding system, process humidity control, and black powder conveyance systems. 18 Inert material began to be processed through the plant during prove-out in 1980. 9

The deficiency correcting process was completed on schedule and within cost in February 1982, although some minor modifications were conducted until August. 9 In February and March 1983, 2,200 pounds of black powder was produced.

The new Black Powder Manufacturing Facility concluded its live explosive prove-out on April 15, 1983, 18 and the facility was formally dedicated on April 22 after nine years of development. 18 It was one of two such plants in the nation, the other at Scranton Army Ammunition Plant in Scranton, Pennsylvania.

Despite the Black Powder Manufacturing Facility’s completion, it was deactivated following prove-out and was not reactivated as it would not be able to meet production quotas because of an outdated computer system dating to 1974 and design flaws. 23

Elsewhere, a semi-automated loading line for 105mm charges was completed in 1980 followed by a semi-automated loadingel line for 8 inch and 155mm charges in 1981. 10 Both facilities were placed into standby status.

Post Cold War

INAAP’s fortunes and employment levels were closely tied to military contracts and military engagements. During the Vietnam War, employment numbers were sustained at around 19,600 workers but this dropped to just 700 workers by 1976 as the conflict began winding down. 10 During the height of the Cold War in the 1980s, 1,500 contractors worked on-site. A decline in military contracts led to major layoffs in 1987.

Seeking a way to reuse INAAP’s vast facilities, officials sought to land Atlantic Research Corporation’s new production plant for the production of advanced solid rocket motors for NASA’s space shuttles on the site of IOW2 and the Black Powder Manufacturing Facility. 17 Ultimately, it chose to locate at an unfinished Tennessee Valley Authority’s nuclear power plant in Yellow Creek, Mississippi 10 17 in 1987. 20

There was also hope that INAAP would be a forerunner for a $350 million 22 research explosives production plant to supplement the sole RDX facility at Holston Army Ammunition Plant in Kingsport, Tennessee. 13 In the event of a military attack, sabotage, or accident, it was feared that the production capability of RDX would be immobilized if production efforts remained solely at one site. In addition, the Holston plant had insufficient space for the construction of additional production facilities and had been operating beyond its design capabilities for years. Other contenders were the Iowa Ammunition Plant site in Middletown, Iowa, the Joliet Army Ammunition Plant in Joliet, Illinois, and the Louisiana Army Ammunition Plant in Shreveport, Louisiana.

The proposed RDX plant at INAAP would cover 25 to 50 acres, employ 300, and be capable of producing 2½ million pounds of RDX per month.10 22 Congress allotted $75,000 for an environmental impact study for the RDX plant at INAAP. 22 In the end, the RDX facility was never built.

In February 1989, the Army sought a private firm to operate the automated Black Powder Manufacturing Facility for 20 to 25 years. 16 23 Three companies, GOEX of Moosic, Pennsylvania, Ensign-Bickford Industries, and ICI America toured the facility, however, no decision was made to utilize the plant.


The failure to land the booster rocket plant and the RDX factory, and a reduction of production orders after nearly a decade of stockpiling charges over the Cold War, convinced the Army to consider the closure of INAAP. The facilities had become outdated and its functions were replaced with modern facilities that utilized a faction of the space and workforce. 32 Technology and progress had simply passed INAAP. On March 10, 1989, approximately one-third of the workforce at INAAP were laid off, including 388 production and maintenance jobs, 51 technical positions, 39 clerical and secretarial jobs, 86 management and supervisory positions, and one guard. 15

Production at INAAP ceased in August 1991 and the Army was prepared to lay off 1,003 employees. 12 U.S. Representative Lee Hamilton and U.S. Senator Dan Coats, however, helped INAAP obtain two munitions orders to prepare a line of propellant charges for other Army depots and to produce a large quantity of 155mm propellant charges. Production at INAAP ceased again after the contract was completed in October 1992 and 750 were laid off. 10

During its tenure from 1941 to 1992, INAAP had produced 3.2 billion pounds of black powder. 30

After its closure, the INAAP was placed into a modified caretaker status and maintained by ICI America. 1 Under the Armament Retooling and Manufacturing Support (ARMS) legislation, the company was permitted to seek long-term adaptive reuse of INAAP with the goal of reducing property holding costs while maintaining military ownership. 29 When ICI America executives approached the county about sharing reuse proceeds and paying to have a study on the issue completed, the county lobbied for total control of INAAP’s grounds.

In 1994, the Army plant commander’s office closed its post and INAAP was transferred to civilian patrol. 2 The facility’s maintenance was transferred to Tecumseh Professional Services who sought to construct an industrial park on part of INAAP’s sprawling grounds. On May 9, 1995, INAAP was renamed Facility One. 1

Several lawsuits were filed by local municipalities and the county over attempts by several communities to annex parts of INAAP. 10 To quell the issue, Congressman Lee Hamilton sponsored special legislation in 1997 that would transfer 6,000 acres of INAAP to the Clark County Reuse Authority (then known as the INAAP Reuse Authority) for redevelopment under a long-term lease. The remaining 4,000 acres would go to the formation of Charlestown State Park. 29 On November 30, 2000, the Army signed an interim lease agreement with the Clark County Reuse Authority.


INAAP featured immense environmental problems from 50 years of black powder and explosive material manufacturing. 10 An environmental study conducted in 1995 identified 87 contaminated areas with another 53 areas cited as potential problems. 10 A follow-up study in 1998 estimated that it would take more than $250 million to remedy the environmental issues. Another study by the Army Corps of Engineers pegged the cost at $33 million. 6 Over 1,000 buildings would require remediation and demolition. 26

A master development plan released in June 2001 by Facility One’s successor River Ridge called for a fifth of INAAP’s grounds to be redeveloped for light industrial use, which included the demolition of all of ammunition production buildings. 8

Demolition began on INAAP’s Igniter Lines on February 6, 2004. 24 As they contained gunpowder dust and other explosive residues, the 64 buildings were set ablaze during times when winds were predominately out of the west or southwest. 25 The burns left elevated levels of lead present in the local atmosphere for a brief period of time, and the winds carried any contamination toward unpopulated areas. 27

On June 1, 2005, the Army granted River Ridge title to 2,308 acres of INAAP at the cost of $1,131 per acre. 31 Twenty-four additional acres consisting of administration buildings were transferred in April 2008 and were converted into the Charlestown Business Center and Wilson Education Center. 28

The two coal power plants, unused since 1992, were demolished from October 2011 until late 2012 at the cost of $1.1 million. 33 The contract, awarded to ADS Trinity, involved scrapping 335 tons of salvageable materials from the site and the demolition of the 120,000 and 145,000 square-foot structures and their 180-foot smokestacks.

Administration Area

Igniter Lines

The Igniter Lines in IOW2 were to bag black powder.

Propellant & Explosives Area

Storage & Shipping Area



Air Test House

After packing the powder into shipping containers, the powder is taken to the Air Test House where each container is checked to ensure that it is air-tight. This is done to prevent the powder from collecting moisture which can modify its ballistic nature.

Blending & Wringler House Building 113

The Blending and Wringer House was part of the nitration process. In order to obtain a uniform propellant and ballistic characteristic, portions of batches that have a high nitrogen content are mixed with portions that have a low nitrogen content. Slurry from the poaching tubs in the Poaching House was fed onto vibrating screens where nitrocellulose was blended, which passed into collecting boxes. The boxes were then emptied into tubs where guncotton and pyrocellulose were blended. If the sample from the tub had satisfactory nitrogen and solubility content, the slurry was pumped into the Wringer House. At the Wringer House, the large amounts of water that were used throughout the process to move the nitrocellulose are removed. The containers of partially dry nitrocellulose are transported to the Dehydration/Press House via lag cars.

Change House Building 707

Comfort Station Building 727

Control Circulation Dry House Building 220

The Control Circulation Dry House dried the remaining solvent out of the powder before it went to the blending tower, where it would be blended to achieve a set burn rate.

Cotton Dry House Building 104

The Cotton Dry House is where cotton linters, or short fibers that cling to cottonseeds after the first ginning was delivered in 150-pound bales or wood pulp delivered in rolls of 700 pounds, where they were shredded. They were then pretreated in large ovens to reduce the moisture to less than 1% before being blown in ducts to the Nitrating House.

Debagging Building 218-1A

Dehy Press House Building 202

The Dehy Press Houses (Building 202) pressed the cake of nitrocellulose into a powder form.

Ether-Mix House Building 206

Horizontal Press House Building 211

Knife Grinding & Die Shop Building 217-2