Aberdeen Proving Ground
Aberdeen, Maryland
This sign on U.S. Route 40 in Aberdeen, Maryland commemorates the establishment of Aberdeen Proving Ground in 1917.
Aberdeen Proving Ground is located in Maryland
Aberdeen Proving Ground
Aberdeen Proving Ground
Location of Aberdeen Proving Ground
Aberdeen Proving Ground is located in the United States
Aberdeen Proving Ground
Aberdeen Proving Ground
Aberdeen Proving Ground (the United States)
Coordinates39°28′24″N 76°08′27″W / 39.473451°N 76.140837°W / 39.473451; -76.140837
Site information
OwnerUS Army
Site history
Built1917; 107 years ago (1917)
In use1917–present
Garrison information
Major General Robert L. Edmonson II

Aberdeen Proving Ground (APG) is a U.S. Army facility located adjacent to Aberdeen, Harford County, Maryland, United States. More than 7,500 civilians and 5,000 military personnel work at APG. There are 11 major commands among the tenant units, including:


Edgewood Arsenal under construction, 1917
Edgewood Arsenal under construction, 1917
Edgewood Arsenal under construction, 1917
Chemical plant at Edgewood Arsenal, 1917

APG is the U.S. Army's oldest active proving ground, established on 20 October 1917, six months after the U.S. entered World War I.[1][2] The planning and construction were overseen by Brigadier General Colden Ruggles, who later served as the Army's Chief of Ordnance.[3] Its location allowed design and testing of ordnance materiel to take place near contemporary industrial and shipping centers. The proving ground was created as a successor to the Sandy Hook Proving Ground, which was too small for some of the larger weapons being tested. At the peak of World War II, APG had billeting space for 2,348 officers and 24,189 enlisted personnel.

Prompt critical excursion

Aberdeen was home to the Army Pulse Radiation Facility Reactor, in 1968. On 6 September 1968, this reactor was the site of a prompt critical excursion during commissioning tests. This accident harmed no personnel but did release enough heat to reach the melting point of the fuel in the core, 1150°C. This caused damage to the fuel components of the reactor, fusing the four central rings together. This is one of thirty-three prompt critical accidents worldwide, between 1949 and 2000.[4]

Base Realignment and Closure program

Under the Base Realignment and Closure (BRAC) program, as announced in 2005, the APG is projected to lose the Ordnance School and associated R&D facilities with 3862 military and 290 civilian jobs moving to Fort Gregg-Adams, Virginia. APG will gain 451 military and 5,661 civilian jobs from Fort Monmouth, New Jersey. As a result, the net change is a loss of 3,411 military jobs and a gain of 5,371 civilian jobs.

Edgewood Arsenal

View of chemical plants, 1918

Although civilian contractors produced the major portion of conventional munitions for World War I, the United States government built federally owned plants on Aberdeen Proving Ground for the manufacture of toxic gas. These poison gas manufacturing facilities came to be known as Edgewood Arsenal. Edgewood Arsenal included plants to manufacture mustard gas, chloropicrin and phosgene, and separate facilities to fill artillery shells with these chemicals. Production began in 1918, reached 2,756 short tons (2,500 t) per month, and totaled 10,817 short tons (9,813 t) of toxic gas manufactured at Edgewood Arsenal before the November 1918 armistice. Some of this gas was shipped overseas for use in French and British artillery shells.[5]

The Edgewood area of Aberdeen Proving Ground is approximately 13,000 acres (5,300 ha) or 20.31 square miles (52.6 km2). The Edgewood area was used for the development and testing of chemical agent munitions. From 1917 to the present, the Edgewood area conducted chemical research programs, manufactured chemical agents, and tested, stored, and disposed of toxic materials.[6]

Main article: Edgewood Arsenal human experiments

From 1955 to 1975, the U.S. Army Chemical Corps conducted classified medical studies at Edgewood Arsenal, Maryland. The purpose was to evaluate the impact of low-dose chemical warfare agents on military personnel and to test protective clothing and pharmaceuticals. About 7,000 soldiers took part in these experiments that involved exposures to more than 250 different chemicals, according to the Department of Defense (DoD). Some of the volunteers exhibited symptoms at the time of exposure to these agents but long-term follow-up was not planned as part of the DoD studies.[7]

The agents tested included chemical warfare agents and other related agents:[7]

During the week of July 14, 1969, personnel from Naval Applied Science Laboratory in conjunction with personnel from Limited War Laboratory conducted a defoliation test along the shoreline of Poole's Island, Aberdeen Proving Ground using Agent Orange and Agent Orange Plus foam.[8]

The Gunpowder Meetinghouse and Presbury Meetinghouse located within the grounds of Edgewood Arsenal are listed on the National Register of Historic Places.[9]

Other component locations within Aberdeen Proving Ground

See also: Edgewood Chemical Biological Center

Other parts of APG not attached to the main installation include the Churchville Test Area in Harford County, and the Carroll Island and Graces Quarters in Baltimore County, Maryland. The Churchville Test Area is a test track with hills that provide steep natural grades and tight turns to stress engines, drivetrains, and suspensions for army vehicles, including M1 Abrams tanks, Bradley Fighting Vehicles, and Humvees.

The eastern half of Carroll Island was used as a testing location for open air static testing of chemical weapons since the 1950s. During tests of chemical agents and other compounds at Carroll Island, Maryland, from July 1, 1964, to December 31, 1971, nearly 6.5 short tons (5.9 t) of chemicals were disseminated on the test area including 4,600 pounds (2,100 kg) of irritants, 655 pounds (297 kg) of anticholinesterase compounds such as the nerve gasses Sarin and VX, and 263 pounds (119 kg) of incapacitants such as LSD. Simulant agents, incendiaries, decontaminating compounds, signaling and screening smokes, mustard, and herbicides were also released as well as riot control gasses. The test sites consisted of spray grids, a wind tunnel, test grids, and small buildings.[10]

Edgewood Chemical Activity is a chemical-weapons depot located at APG. Elimination of the chemicals held here was put on an accelerated schedule after the September 11, 2001, attacks, and all chemical weapons were destroyed by February 2006.

Fort Hoyle was established on October 7, 1922, and was created from a portion of the Edgewood Arsenal. Named for Brigadier General Eli D. Hoyle, who had commanded the 6th Field Artillery Regiment, the post was home to Headquarters, 1st Field Artillery Brigade (1922 to 1939), the 6th Field Artillery Regiment (1922 to 1940), the 1st Ammunition Train (1922 to 1930), and the 99th Field Artillery Regiment (minus 2nd Battalion) (1940 to 1941). Fort Hoyle was officially disestablished as a separate military post when it was reabsorbed by Edgewood Arsenal on September 10, 1940.[11][12]

The U.S. Army Ordnance Corps Museum previously located at APG, was moved to Fort Gregg-Adams, Virginia, as a result of the 2005 Base Realignment and Closure (BRAC) Act.


APG is located at 39°28′24″N 76°8′27″W / 39.47333°N 76.14083°W / 39.47333; -76.14083[13] and occupies a land area of 293 square kilometres (113 sq mi).[14] Its northernmost point is near the mouth of the Susquehanna River, where the river enters the Chesapeake Bay, while on the south, it is bordered by the Gunpowder River. The installation lies on two peninsulas separated by the Bush River. The northeastern is known as the Aberdeen Area and the southwestern is called the Edgewood Area (formerly the Edgewood Arsenal).

According to the U.S. Census Bureau, the CDP has a total area of 12.0 square miles (31.1 km2), of which 11.4 square miles (29.5 km2) is land and 0.6 square miles (1.6 km2) (5.09%) is water.


Historical population
U.S. Decennial Census[15]
2010[16] 2020[17]

For statistical purposes the base is delineated as a census-designated place (Aberdeen Proving Ground CDP) by the U.S. Census Bureau. As of the 2020 census, the resident population was 1,668.[18]

2020 census

Aberdeen Proving Ground CDP, Maryland - Demographic Profile(NH = Non-Hispanic)
Race / Ethnicity Pop 2010[16] Pop 2020[17] % 2010 % 2020
White alone (NH) 1,207 695 57.67% 41.67%
Black or African American alone (NH) 424 471 20.26% 28.24%
Native American or Alaska Native alone (NH) 12 5 0.57% 0.30%
Asian alone (NH) 43 81 2.05% 4.86%
Pacific Islander alone (NH) 15 4 0.72% 0.24%
Some Other Race alone (NH) 8 19 0.38% 1.14%
Mixed Race/Multi-Racial (NH) 76 147 3.63% 8.81%
Hispanic or Latino (any race) 308 246 14.72% 14.75%
Total 2,093 1,668 100.00% 100.00%

Note: the US Census treats Hispanic/Latino as an ethnic category. This table excludes Latinos from the racial categories and assigns them to a separate category. Hispanics/Latinos can be of any race.

2000 Census

As of the census[19] of 2000, there were 3,116 people, 805 households, and 763 families residing in the CDP. The population density was 274.1 inhabitants per square mile (105.8/km2). There were 902 housing units at an average density of 79.3 per square mile (30.6/km2). The racial makeup of the CDP was 50.5% White, 34.6% African American, 0.6% Native American, 3.1% Asian, 1.3% Pacific Islander, 5.7% from other races, and 4.2% from two or more races; 11.2% of the population were Hispanic or Latino of any race.

In the CDP, the population was spread out, with 40.1% under the age of 18, 10.3% from 18 to 24, 44.9% from 25 to 44, 4.4% from 45 to 64, and 0.2% who were 65 years of age or older. The median age was 25 years. For every 100 females, there were 113.9 males. For every 100 females age 18 and over, there were 117.6 males.

The median income for a household in the CDP was $38,875, and the median income for a family was $40,306. Males had a median income of $26,943 versus $26,194 for females. The per capita income for the CDP was $12,808. About 4.2% of families and 5.6% of the population were below the poverty line, including 6.4% of those under age 18 and none of those age 65 or over.


The Edgewood area of the Aberdeen Proving Ground site was proposed to the Environmental Protection Agency's National Priorities List of the most serious uncontrolled or abandoned hazardous waste sites requiring long term remedial action on April 10, 1985. The site was formally added to the National Priorities List on February 21, 1990.[6]

The Edgewood area has large areas of land and water and numerous buildings that are contaminated or suspected of contamination. Virtually all the land areas of the site contain contaminated or potentially contaminated sites and potentially buried ordnance. Substances disposed of in the area include significant quantities of napalm, white phosphorus, and chemical agents. On-site surface waters include rivers, streams, and wetlands.[6]

Edgewood area standby water supply wells in the Canal Creek area previously served approximately 3,000 people. The wells have been abandoned. The Long Bar Harbor well field of the County Department of Public Works and the well field used by the Joppatowne Sanitary Subdistrict serve 35,000 people within 3 miles (4.8 km) of the site. On-site groundwater sampling has identified perchlorate, various metals, volatile organic compounds (VOCs) and chemical warfare agent degradation products. On-site soil contamination sampling has identified various VOCs, metals, and unexploded ordnance in surface and subsurface soil. On-site surface water sampling has identified various metals, pesticides, phosphorus, and VOCs. People who accidentally ingest or come in direct contact with contaminated groundwater, surface water, soil, or sediments may be at risk. The area is a designated habitat for bald eagles.[6]


Chlorine plant at the Edgewood Arsenal, 1918

A scandal at the APG surfaced in 1996. The U.S. Army brought charges against twelve commissioned and non-commissioned male officers for sexual assault of female trainees under their command.[20]

Following campaigning by PETA, the Physicians Committee for Responsible Medicine and other organizations, the U.S. military announced in 2011 that it was replacing its use of monkeys in the Army's nerve-agent attack training courses with human simulators and other non-animal teaching methods. The training drills had been carried out on vervet monkeys and conducted at Aberdeen Proving Ground.[21]

A Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System (JLENS) broke free from its mooring station on APG October 28, 2015. It traveled for three-hours through the skies, finally crashing in a wooded area in northeastern Pennsylvania.[22]

See also


  1. ^ "Army Alliance | Aberdeen Proving Ground | History of APG | Army Alliance | Aberdeen Proving Ground". Archived from the original on 2017-04-29. Retrieved 2017-04-03.
  2. ^ Sun, Baltimore. "Aberdeen Proving Ground". baltimoresun.com. Archived from the original on 2017-05-27. Retrieved 2017-05-03.
  3. ^ Thayer, Bill (May 5, 2015). "Colden L'H Ruggles in Biographical Register of the Officers and Graduates of the United States Military Academy, Volumes III-VIII". Bill Thayer's Web Site. Chicago, IL: Bill Thayer. Retrieved August 8, 2020.
  4. ^ A Review of Criticality Accidents, Los Alamos National Laboratory, LA-13638, May 2000. Thomas P. McLaughlin, Shean P. Monahan, Norman L. Pruvost, Vladimir V. Frolov, Boris G. Ryazanov, and Victor I. Sviridov.
  5. ^ Ayres, Leonard P. (1919). The War with Germany (Second ed.). Washington, DC: United States Government Printing Office. pp. 79&80.
  6. ^ a b c d "Aberdeen Proving Ground (Edgewood Area Site) Current Site Information". EPA Mid-Atlantic Superfund sites. Environmental Protection Agency. January 2013. Archived from the original on October 4, 2013. Retrieved October 1, 2013.
  7. ^ a b "Edgewood / Aberdeen Experiments". VA Public Health Military Exposures. United States Department of Veterans Affairs. April 1, 2013. Archived from the original on October 4, 2013. Retrieved October 1, 2013.
  8. ^ Information from Department of Defense (DoD) on Herbicide Tests and Storage outside of Vietnam (PDF) (Report). Department of Veterans Affairs. May 25, 2012. p. 5. Archived (PDF) from the original on June 11, 2014. Retrieved December 2, 2013.
  9. ^ "National Register Information System". National Register of Historic Places. National Park Service. July 9, 2010.
  10. ^ Richard Albright (29 May 2013). Death of the Chesapeake: A History of the Military's Role in Polluting the Bay. Wiley. pp. 82–. ISBN 978-1-118-75666-9. Retrieved 1 October 2013.
  11. ^ Bates, Bill (2007). Aberdeen Proving Ground. Charleston, SC: Arcadia Publishing. p. 62. ISBN 978-0-7385-4436-6.
  12. ^ Murray, Joseph F.; Stuempfle, Arthur K.; Stuempfle, Amy L. (2012). Edgewood. Charleston, SC: Arcadia Publishing. p. 8. ISBN 978-0-7385-9279-4.
  13. ^ "US Gazetteer files: 2010, 2000, and 1990". United States Census Bureau. 2011-02-12. Retrieved 2011-04-23.
  14. ^ Hoiberg, Dale H., ed. (2010). "Aberdeen". Encyclopædia Britannica. Vol. I: A-ak Bayes (15th ed.). Chicago, Illinois: Encyclopædia Britannica Inc. pp. 28. ISBN 978-1-59339-837-8.
  15. ^ "Decennial Census of Population and Housing by Decades". US Census Bureau.
  16. ^ a b "P2 HISPANIC OR LATINO, AND NOT HISPANIC OR LATINO BY RACE - 2010: DEC Redistricting Data (PL 94-171) - Aberdeen Proving Ground CDP, Maryland". United States Census Bureau.
  17. ^ a b "P2 HISPANIC OR LATINO, AND NOT HISPANIC OR LATINO BY RACE - 2020: DEC Redistricting Data (PL 94-171) - Aberdeen Proving Ground CDP, Maryland". United States Census Bureau.
  18. ^ "Aberdeen Proving Ground CDP, Maryland". United States Census Bureau. Retrieved March 13, 2022.
  19. ^ "U.S. Census website". United States Census Bureau. Retrieved 2008-01-31.
  20. ^ "CNN - Three soldiers arraigned in U.S. Army sex scandal - Dec. 6, 1996". edition.cnn.com. Archived from the original on 1 May 2018. Retrieved 1 May 2018.
  21. ^ Vastag, Brian (13 October 2011). "Army to phase out use of animal nerve-agent testing". Washington Post. Archived from the original on 3 April 2015. Retrieved 9 March 2015.
  22. ^ Judson, Jen (2015-10-30). "After Blimp Broke Free and Crashed, JLENS Program Hangs by a Thread". Defense News. Retrieved 2024-02-03.

Further reading

39°28′24″N 76°08′27″W / 39.473451°N 76.140837°W / 39.473451; -76.140837