Four Japanese Self-Defense Forces (JSDF) personnel sustained injuries on Monday after a sudden explosion rocked a storage facility housing unexploded ordnance within a U.S. military installation on the southern Japanese island of Okinawa.
The blast, which occurred during a routine inspection, has raised fresh concerns over the lingering dangers of World War II-era munitions still buried across the island.
Officials confirmed that none of the injuries were life-threatening. The soldiers had been handling an old explosive device at a facility overseen by the Okinawa prefectural government, situated within the munitions zone of Kadena Air Base — a key hub for U.S. military operations in the Pacific.
U.S. Air Force representatives clarified that no American military personnel were involved in the incident.
Preliminary accounts suggest the explosion happened as the JSDF team was attempting to remove corrosion from the old device. While the exact cause is still under investigation, authorities suspect the aging ordnance may have become unstable during the cleaning process.
The facility in question serves as a temporary storage location for recovered wartime munitions — the vast majority dating back to the final stages of World War II. Okinawa, a key battleground during the war, remains heavily affected by leftover explosives. Construction workers and land developers frequently unearth unexploded bombs, a grim reminder of the island’s violent past.
Estimates suggest over 1,800 tons of U.S.-dropped bombs still lie buried beneath Okinawa’s soil. Japan’s ordnance disposal operations, run by the JSDF, have been dealing with these dangerous remnants for decades. Monday’s explosion is the first such serious accident involving the unit since its formation in 1974.
The incident follows a similar scare in October last year, when a buried WWII-era bomb exploded at a commercial airport in southern Japan, forming a large crater and forcing the suspension of air traffic.
As investigations continue into the cause of Monday’s blast, local authorities and military officials are calling for reinforced safety protocols. The event has reignited debate over the burden Okinawa bears in hosting both a significant concentration of American military bases and the risks posed by legacy weapons still haunting its landscape.
While the injured soldiers are expected to recover, the incident has highlighted the ongoing peril these decades-old explosives continue to pose — not just to military personnel, but to the wider public living and working across the island.