Newly discovered documents reveal that 50 years ago this week, the Pentagon dispatched a chemical weapons platoon to Okinawa under the auspices of its infamous Project 112. Described by the U.S. Department of Defense as "biological and chemical warfare vulnerability tests," the highly classified program subjected thousands of unwitting American service members around the globe to substances including sarin and VX nerve gases between 1962 and 1974.

According to papers obtained from the U.S. Army Heritage and Education Center in Carlisle, Pennsylvania, the 267th Chemical Platoon was activated on Okinawa on Dec. 1, 1962, with "the mission of operation of Site 2, DOD (Department of Defense) Project 112." Before coming to Okinawa, the 36-member platoon had received training at Denver's Rocky Mountain Arsenal, one of the key U.S. chemical and biological weapons (CBW) facilities. Upon its arrival on the island, the platoon was billeted just north of Okinawa City at Chibana — the site of a poison gas leak seven years later. Between December 1962 and August 1965, the 267th platoon received three classified shipments — codenamed YBA, YBB and YBF — believed to include sarin and mustard gas.

For decades, the Pentagon denied the existence of Project 112. Only in 2000 did the department finally admit to having exposed its own service members to CBW tests, which it claimed were designed to enable the U.S. to better plan for potential attacks on its troops. In response to mounting evidence of serious health problems among a number of veterans subjected to these experiments, Congress forced the Pentagon in 2003 to create a list of service members exposed during Project 112. While the Department of Defense acknowledges it conducted the tests in Hawaii, Panama and aboard ships in the Pacific Ocean, this is the first time that Okinawa — then under U.S. jurisdiction — has been implicated in the project.