One-Million-Liter Test Sphere

The One-Million-Liter Test Sphere at Fort Detrick, Maryland, was a decommissioned U.S. Army biological warfare testing facility and the largest aerobiology chamber ever built. Conceived by Herbert G. Tanner, it was constructed in 1947 and 1948, became operational in 1950, and supported Army biological warfare research from 1951 to 1969. The four-story stainless steel sphere was designed to contain internal detonations of biological munitions while scientists studied infectious aerosols. Animals were used in exposure experiments, and human volunteers participated in controlled inhalation studies, including Operation Whitecoat. After the offensive program ended in 1969, the surviving chamber was listed on the National Register of Historic Places in 1977.

Frederick, Maryland · United States