LAKEWOOD, Colo. (CBS4) – Crews worked carefully on Wednesday to clean up munitions from World War II in Lakewood’s Green Mountain Park.

So far nine explosives have been found and safely destroyed. The issue first arose in 2008 when a grass fire on Green Mountain revealed some buried munitions.

The National Guard said the area was used for artillery training as an impact area for 75-millimeter high-explosive and shrapnel projectiles.

Officials say it will be a few years before the area is completely cleaned up.