Each year, several tons of unexploded shells are recovered. According to the Sécurité Civile agency in charge, at the current rate 300[2] to 700 more years will be needed to clean the area completely. Some experiments conducted in 2005–06 discovered up to 300 shells per hectare (120 per acre) in the top 15 cm (6 inches) of soil in the worst areas.[3]