When the last U.S. service members moved out of the Nishi-Futenma housing area at Camp Foster, in 2006, the land was slated to return to civilian use as part of ongoing attempts by Tokyo and Washington to reduce the military burden in Okinawa — host to more than 70 percent of American bases in Japan.

The reversion of the 52-hectare parcel — an attractive hilltop overlooking the East China Sea — was supposed to be a sign of improved ties between the U.S. military and its Okinawa neighbors. But instead it has come to signify a problem that is increasingly straining relations in the prefecture: military pollution.

Seven years after the land at Nishi-Futenma was vacated, its future is still in limbo. The dozens of beige bungalows that used to house U.S. families are abandoned — their screen doors torn and walls overgrown with vegetation.