"While conducting training, an F-16 at Misawa [Air Base] released a device 5 kilometres [3 miles] from the Draughon range late Wednesday. The cause of the incident is still under investigation, and USFJ notified GOJ [Government of Japan] this morning in accordance with all agreements", the command said on Twitter.
2/2 There have been no reports of injury or damage. USFJ takes safety seriously and Misawa has suspended inert drops until further notice.— U.S. Forces Japan (@USForcesJapan) November 7, 2019
This incident highlights the importance of realistic training to ensure safety of operations.
Similar incidents involving US military aircraft stationed in Japan have happened in recent years. In particular, at least two helicopters made emergency landings in residential areas of Okinawa prefecture, and a 10-year-old student suffered a minor injury after a helicopter window fell onto a local school.
In a more serious incident, three servicemen were killed off the coast of Okinawa when a C2-A aircraft with 11 people on board crashed into the Pacific Ocean in November 2017. A month earlier, a CH-53 helicopter made an emergency landing on private property before bursting into flames.