frostbite or trench foot injuries; heat stroke; food poisoning not caused by enemy agents; chemical, biological, or nuclear agents not released by the enemy; battle fatigue; disease not directly caused by enemy agents; accidents, to include explosive, aircraft, vehicular, and other accidental wounding not related to or caused by enemy action; self-inflicted wounds (e.g., a soldier accidentally fires their own gun and the bullet strikes their leg), except when in the heat of battle, and not involving gross negligence; post-traumatic stress disorders;[5] and jump injuries not caused by enemy action.