text: FM 7-100.1________________________________________________________________________________
  OFFENSIVE CHEMICAL EMPLOYMENT
  11-23. The basic principle of chemical warfare is to achieve surprise. It is
  common to mix chemical rounds with high-explosive (HE) rounds in order to
  achieve chemical surprise. Chemical casualties inflicted and the necessity of
  chemical protective gear degrade enemy defensive actions. The OPFOR also
  may use chemical agents to restrict the use of terrain. For example, contami-
  nation of key points along the enemy’s lines of communication can seriously
  disrupt his resupply and reinforcement, while simultaneously keeping those
  points intact for subsequent use by the attacking OPFOR.
  11-24. Nonpersistent agents are suitable for use against targets on axes the
  OPFOR intends to exploit. While possibly used against deep targets, their
  most likely role is to prepare the way for an assault by maneuver units,
  especially when enemy positions are not known in detail. The OPFOR may
  also use nonpersistent agents against civilian population centers in order to
  create panic and a flood of refugees.
  11-25. Persistent agents are suitable against targets the OPFOR cannot de-
  stroy by conventional or precision weapons. This can be because a target is
  too large or located with insufficient accuracy for attack by other than an area
  weapon. Persistent agents can neutralize such targets without a pinpoint attack.
  11-26. In the offense, likely chemical targets include—
  • Troops occupying defensive positions, using nonpersistent agents delivered
  by MRLs to neutralize these troops just before launching a ground attack.
  Ideally, these nonpersistent agents would be dissipating just as the at-
  tacking OPFOR units enter the area where the chemical attack occurred.
  • NBC delivery systems, troop concentration areas, headquarters, and
  artillery positions, using all types of chemical agents delivered by tube
  artillery, MRLs, missiles, and aircraft.
  • Bypassed pockets of resistance (especially that pose a threat to the
  attacking forces), using persistent agents.
  • Possible assembly areas for enemy counterattack forces, using persis-
  tent agents.
  11-27. The OPFOR could use chemical attacks against such targets simulta-
  neously throughout the enemy defenses. These chemical attacks combine
  with other forms of conventional attack to neutralize enemy nuclear capability,
  C2 systems, and aviation. Subsequent chemical attacks may target logistics
  facilities. The OPFOR would use persistent agents deep within the enemy’s
  rear and along troop flanks to protect advancing units.
  DEFENSIVE CHEMICAL EMPLOYMENT
  11-28. When the enemy is preparing to attack, the OPFOR can use chemical
  attacks to disrupt activity in his assembly areas, limit his ability to maneuver
  into axes favorable to the attack, or deny routes of advance for his reserves.
  Once the enemy attack begins, the use of chemical agents can impede an attack-
  ing force, destroying the momentum of the attack by causing casualties or caus-
  ing attacking troops to adopt protective measures. Persistent chemical agents
  can deny the enemy certain terrain and canalize attacking forces into kill zones.