WITH U.S. TROOPS, SAUDI ARABIA -- With a major ground war seemingly imminent, U.S. commanders say they are certain that Iraq will use chemical weapons against U.S. soldiers.
That will leave the first U.S. troops entering Kuwait fighting in gas masks and bulky chemical protective suits, cutting down their effectiveness and slowing the pace of battle.
In reaching their conclusion, the commanders are depending on a flurry of recent intelligence gathered from captured Iraqi troops and other sources:
* Iraq distributed different types of chemical rounds to division commanders, apparently giving these leaders the authority to use them in ground combat, military intelligence sources say.
* The Iraqis may be putting cyanide in rocket-propelled grenades and other types of rounds, one officer said, giving them the ability to kill a tank crew and take over the vehicle. Reconnaissance teams along the Kuwaiti and Iraqi borders have noticed strange puffs of gray smoke from exploding RPG rounds that could indicate cyanide gas.
* The Iraqis have managed to hide all of their Scud-B mobile launchers from U.S. aircraft, meaning that they probably still have their main battlefield missile intact.
The Scud-B missile, which has a range of 180 miles, is the original model that Iraq purchased from the Soviet Union during the 1970s. It would be Iraq's best means of attacking U.S. troops with chemicals such as nerve and mustard agents, one source said.
So far, all of the launchers and missiles that U.S. fighter-bombers have destroyed have been two Iraqi-modified versions of the Scud called the Al-Hussein and the Al-Abbas, which can travel farther.
Taken together, this evidence has convinced commanders that U.S. troops will be wearing all of their chemical gear as they make their way through the extensive fortifications Iraq has built inside Kuwait.
"I'm convinced they're going to use chemicals," said Col. Samuel Raines, commander of the U.S. Army's 7th Engineer Brigade.
"This war will be chemical probably from the very first hour," said a military intelligence officer. "I don't think the troops understand that yet.
"Personally, I think it's another miscalculation on his [Saddam Hussein's] part. He seems to think it's going to sap our will to fight, but I think it's just going to p - - - off American troops more.
"There's a big difference between seeing your buddy blown apart and seeing him twitching to death right next to you."
U.S. troops are preparing for a chemical assault in the form of Scud missiles, grenades, helicopter spraying -- even chemical-filled land mines.
Commanders concede that apart from chemical protective suits and good training, there is little they can do to stop chemicals from hitting their soldiers.
"They could launch two dozen helicopters with aerosol containers to spray our troops from the air," said an intelligence officer. "Even if we got all but two or three, that would be enough as far as they're concerned."
"It's a realistic threat to the effect that if you shoot down that helicopter, you still have a chemical hazard," said Capt. Jack Hinkley, a chemical weapons expert with the 7th Brigade. "And you've shot it down over your own positions, probably."
The novel use of placing chemicals such as cyanide in RPG rounds -- if true -- doesn't frighten commanders as much as Scud missiles and chemical bombs. At best, cyanide grenades would kill limited numbers of troops, since cyanide dissipates in about 10 minutes.
The threat would be to M-1A1 tanks and other airtight systems, but that would require pinpoint accuracy, commanders say. The idea might be that Iraqi troops could then decontaminate the tank, fix it and drive it off.
"If you're in an overpressurized [airtight] system with cyanide gas, then you're in trouble," said an intelligence officer. "If they managed to penetrate the tank and you don't get out, it would eat away at your mask."
If they use chemicals, the Iraqis may follow a standard Soviet doctrine that calls for Scud missile attacks on logistics bases, command centers and other posts behind the front lines. That forces everyone into a high chemical alert even if the danger is only limited to a small site.
As a result, battlefield effectiveness probably would be reduced as much as 15 percent to 25 percent, said Col. Robert Thornton, chief chemical officer with the U.S. Army's 7th Corps.
In chemical battlefield exercises conducted at Fort Hood, Texas, U.S. Army researchers found that troops wearing chemical gear used their radios more than was necessary. They also relied more heavily on calling in artillery strikes rather than using their own weapons.