When the US military handed over control of the Panama Canal in 1999, it left behind thousands of unexploded weapons strewn across jungle firing ranges that are still killing people.
Many Panamanians accuse the United States of ignoring the dangers and President George W. Bush will face protests over the controversy during a visit starting on Sunday night.
Washington controlled the inter-oceanic waterway and a five-mile (eight km) strip either side of the canal for almost all of the 20th century, and used some of the land for firing ranges.
It gave control of the canal to Panama at the end of 1999, but handover treaties only obliged it to clear up unexploded munitions as far as was "practicable."
Around 30,000 acres were cleaned but 8,000 acres are still scattered with live mortars, grenades, bombs, rockets and Agent Orange residue.
Outside the canal zone, seven mustard gas bombs weighing between 500 pounds and 1,000 pounds were abandoned on Panama's uninhabited Pacific island of San Jose. Officially, 21 people have been killed in the firing ranges over the years, although some believe the true figure is more than double that.
Sabino Rivera was the most recent victim, killed in July 2004 near his home in the village of Escobal, three hours from the capital. "He had nine children, and was gathering bananas in the firing range - he had no work. He exploded when he stood on a mortar.
He never came home," his mother Blasina said this week, cradling her grandchildren in a breeze block shack. The village is surrounded by bomb-infested rain forest ranges that poor locals still enter to hunt and farm.