Last updated: November 19, 2025
Article
Staten Island Warehouse
The Manhattan Project took its name from an office in downtown Manhattan where planning began for what would become one of the most complex and collaborative military and industrial efforts in history. By chance, in the nearby borough of Staten Island, a warehouse already held the essential ingredient that the Manhattan Project needed to develop atomic weapons — uranium.
Union Minière was a mining company that controlled the copper, cobalt, and uranium found in what is now the Democratic Republic of Congo. One of the mines Union Minière operated was Shinkolobwe, which held one of the purest deposits of uranium in the world. However, prior to World War II, uranium was not a highly sought-after material. At the time, uranium-bearing ores were mostly mined for radium that was often found nearby. Radium was used as a cancer treatment and for luminous paint, and radium prices surged during the early twentieth century. This made the Shinkolobwe mine a huge moneymaker for Union Minière until demand for radium declined in the 1930s. Eventually, the Shinkolobwe mine fell into disrepair.
The man with oversight of the Shinkolobwe mine was Edgar Sengier, a Belgian mining engineer who rose through the ranks of Union Minière to become director. When Shinkolobwe flooded, Sengier decided not to clean it up, not seeing the value compared to Union Minière’s other more financially prudent ventures. However, his opinion would change after a trip to London, where he was warned by British scientists about the potential danger if the resources in the Shinkolobwe mine were to get into the hands of the Germans. The British and the French both offered to purchase the uranium, showing Sengier its enhanced value.
To prevent the uranium from getting into Germany’s hands, as well as protect Union Minière’s assets and potentially sell to a higher bidder, Sengier decided to ship half of Shinkolobwe’s stores of uranium ore, about 1,200 tons, to the United States in 1940. Needing a storage location big enough to hold the barrels stamped “Uranium Ore — Product of Belgian Congo” on short notice, he stockpiled the ore in a three-story warehouse in Staten Island, New York, near the Bayonne Bridge. The stores would sit untouched for more than two years while Sengier conducted business for Union Minière in Manhattan, mere blocks from the office for the Manhattan Project.
Sengier attempted to sell the uranium to the U.S. government, at first to no avail. Shortly after the attack on Pearl Harbor on Dec. 7, 1941, a representative of the U.S. State Department approached Sengier about the nation’s desperate need for cobalt. Sengier’s suggestion that they should be interested in Union Minière’s uranium instead went unheeded.
The situation changed when Sengier applied to the U.S. State Department in the fall of 1942 for a license to ship some of Union Minière’s uranium ore to Canada and word reached Lieutenant Colonel Kenneth D. Nichols, the second in command of the Manhattan Project. Knowing the ore’s value, Nichols quicky arranged for the purchase of the uranium in Staten Island as well as stockpiles of ore still in Africa.
Compared to uranium ores in the Western United States and Canada that provided uranium to the Manhattan Project, the ore from Africa was extremely high grade. Ultimately, Union Minière provided approximately two-thirds of the uranium acquired by the Manhattan Project. Arguably, without the uranium ore from the Congo, the Manhattan Project would have been unable to produce the atomic bombs dropped on Japan during World War II.
The U.S. Department of Energy Office of Legacy Management’s Formerly Utilized Sites Remedial Action Program maintains an online Considered Sites Database that provides digital access to some 1,500 key documents related to sites that supported the Manhattan Project and the U.S. Atomic Energy Commission, including the Staten Island Warehouse.
Union Minière was a mining company that controlled the copper, cobalt, and uranium found in what is now the Democratic Republic of Congo. One of the mines Union Minière operated was Shinkolobwe, which held one of the purest deposits of uranium in the world. However, prior to World War II, uranium was not a highly sought-after material. At the time, uranium-bearing ores were mostly mined for radium that was often found nearby. Radium was used as a cancer treatment and for luminous paint, and radium prices surged during the early twentieth century. This made the Shinkolobwe mine a huge moneymaker for Union Minière until demand for radium declined in the 1930s. Eventually, the Shinkolobwe mine fell into disrepair.
The man with oversight of the Shinkolobwe mine was Edgar Sengier, a Belgian mining engineer who rose through the ranks of Union Minière to become director. When Shinkolobwe flooded, Sengier decided not to clean it up, not seeing the value compared to Union Minière’s other more financially prudent ventures. However, his opinion would change after a trip to London, where he was warned by British scientists about the potential danger if the resources in the Shinkolobwe mine were to get into the hands of the Germans. The British and the French both offered to purchase the uranium, showing Sengier its enhanced value.
To prevent the uranium from getting into Germany’s hands, as well as protect Union Minière’s assets and potentially sell to a higher bidder, Sengier decided to ship half of Shinkolobwe’s stores of uranium ore, about 1,200 tons, to the United States in 1940. Needing a storage location big enough to hold the barrels stamped “Uranium Ore — Product of Belgian Congo” on short notice, he stockpiled the ore in a three-story warehouse in Staten Island, New York, near the Bayonne Bridge. The stores would sit untouched for more than two years while Sengier conducted business for Union Minière in Manhattan, mere blocks from the office for the Manhattan Project.
Sengier attempted to sell the uranium to the U.S. government, at first to no avail. Shortly after the attack on Pearl Harbor on Dec. 7, 1941, a representative of the U.S. State Department approached Sengier about the nation’s desperate need for cobalt. Sengier’s suggestion that they should be interested in Union Minière’s uranium instead went unheeded.
The situation changed when Sengier applied to the U.S. State Department in the fall of 1942 for a license to ship some of Union Minière’s uranium ore to Canada and word reached Lieutenant Colonel Kenneth D. Nichols, the second in command of the Manhattan Project. Knowing the ore’s value, Nichols quicky arranged for the purchase of the uranium in Staten Island as well as stockpiles of ore still in Africa.
Compared to uranium ores in the Western United States and Canada that provided uranium to the Manhattan Project, the ore from Africa was extremely high grade. Ultimately, Union Minière provided approximately two-thirds of the uranium acquired by the Manhattan Project. Arguably, without the uranium ore from the Congo, the Manhattan Project would have been unable to produce the atomic bombs dropped on Japan during World War II.
The U.S. Department of Energy Office of Legacy Management’s Formerly Utilized Sites Remedial Action Program maintains an online Considered Sites Database that provides digital access to some 1,500 key documents related to sites that supported the Manhattan Project and the U.S. Atomic Energy Commission, including the Staten Island Warehouse.