Old and abandoned chemical weapons (OACW) must meet specific criteria concerning their date of manufacture, physical condition, and date of abandonment before they are verified as meeting the definition of old or abandoned. As with the chemical weapons in normal storage, this includes projectiles, rockets, mortars, bombs, mines/spray  dispersal devices, and spray tanks. The variety of chemical fills is much greater with weapons manufactured prior to 1946, and includes fills such as mustard, phosgene, tabun, hydrogen cyanide, diphenylchlorarsine, chlorine, stannic chloride, etc.  Recovery and destruction of OACW presents particular difficulty to member States, as CW are frequently mixed with other types of hazardous munitions.  Deterioration of explosive and safety components makes approach and contact with these items highly dangerous, with serious accidents not uncommon.