The Department of Defense (DOD) ESQD hazard classification system is based on a system recommended for international use by the United Nations Organization (UNO). The UNO system has nine classes of hazardous material; but, DOD only uses three of the nine classes—Class 1, explosives; Class 2, Division 3, poison A; and Class 6, poisonous (toxic) and infectious substances. Table 12-4 identifies each of the nine classes. In  reviewing  table  12-4,  you  can  see  that  some items  are  placed  in  classes  other  than  Class  1.  Since DOD  uses  only  Class  1  items  for  explosives,  Class  1 assignments  have  been  made.  However,  to  maintain identity, DOD places these items in Class 1 for storage only  until  DOD  implements  other  classes.  As  an  AO, you are involved with the storage of Class 1 material; therefore, the information contained in this section only deal with Class 1 classifications. DOD Hazard Class 1 is subdivided into divisions 1 through 5, based on the character and predominance of the  associated  hazards  and  the  potential  for  causing personnel    casualties    or    property    damage.    These subdivision are not based upon compatibility groups or intended  use.  The  division  within  Class  1  and  the expected hazard for each division is listed in table 12-5. MASS-DETONATING HAZARD MATE- RIALS (CLASS 1, DIVISION 1).—Damage  from mass-detonating hazard materials is caused by concussion   or   blast   or   by   sympathetic   detonation. Prescribed  distances  between  piles  of  these  materials and   between   magazines   containing   these   materials must   be   maintained   to   minimize   the   possibility   of sympathetic  detonation  or  propagation.  Ammunition and   explosives   that   are   considered   mass-detonating hazards are Hazard Class 1, Division 1. NON-MASS-DETONATING HAZARD, FRAG- MENT-PRODUCING MATERIALS (CLASS 1, DIVISION 2).—The   principal   hazards   for   items within   this   division   are   fragment   and   blast,   either individually   or   in   combination,   depending   on   such factors  as  storage  configuration,  type  of  packing,  and quantity. The designated minimum distances are based upon  the  limited  range  of  fragments.  These  are  the distances that must be used for protection of inhabited buildings  and  public  traffic  routes.  Since  fragment- producing  materials  can  be  grouped  according  to  the 12-6 CLASS TYPE OF HAZARDOUS MATERIAL 1 2* 3 4 5 6* 7 8 9 Ammunition and explosives, DOT Classes A, B, and C; Blasting Agents Compressed gases, flammable and nonflammable, Poison gases (Poison A) Flammable liquids Flammable solids or substances Oxidizing materials Poisonous substances (Poison B); Irritating materials; Etiological agents Radioactive materials Corrosive materials Miscellaneous dangerous substances (other regulated materials) *Includes   ammunition   without   explosive   components   which   contain   toxic   chemical   agents,   and containers of toxic chemical agents in bulk. Formerly ESQD Class 8. Table 12-4.—United Nations Organization Hazard Classes