The story of the unexploded ordinances (UXO) on Green Mountain is echoed around the country and world. My dad and I used to hike a lot at Croft State Park in South Carolina which was another army training camp. Signs are posted on every trail in Croft warning about the dangers of picking any metal object. Green Mountain needs signs telling people of the danger (I didn't find anything warning people!). I am happy though that geophysics can be used to identify the shells and get them out of there. I just wish they could get it done! Have you encountered any unexploded artillery shells, grenades, etc? Do you know the areas in your state that could be dangerous? Go here to find the report on the UXO sites by state in America and it's territories (these are the ones on private or federal land). If you are in a different country just Google "uxo sites" and the name of the country (there's not a global list). Remember if you're out treasure hunting and you find a UXO: Recognize, Retreat, and Report! Don't chance it!
Update: I was out at Green Mountain over the weekend (10.28.2012) and stumbled upon a sign warning of the danger. It was small and not very noticeable but at least they are out there!