Regarding land mines, 78 countries are contaminated and they kill 15–20,000 people every year while severely maiming countless more.
Approximately 80% of casualties are civilian, with children as the most affected age group.
The landmines are homemade and were placed primarily during the last 25 years of the conflict, hindering rural development significantly.
The rebel groups of FARC and the smaller ELN are usually blamed for having placed the mines.
All departments of Colombia are affected, but Antioquia, where the city of Medellin is located, holds the largest amounts.
The exact cause is not known, but the Marines had been handing grenades they were collecting to each other, which is permitted but discouraged, and it is thought that a grenade may have exploded after being kicked or bumped, setting off hundreds of other grenades and shells.Unexploded ordnance from at least as far back as the American Civil War still poses a hazard worldwide, both in current and former combat areas and on military firing ranges.A major problem with unexploded ordnance is that over the years the detonator and main charge deteriorate, frequently making them more sensitive to disturbance, and therefore more dangerous to handle.Both the Colombian military and FARC are taking part in the demining efforts.The program intends to rid Colombia of landmines and other UXO by 2021 and it has been funded with nearly US2 million, including US million from the US (as part of the larger US foreign policy Plan Colombia) and US.4 million from the EU.