Behind the cocked-and-ready bravado of this tough unit percolated the fear that the Screaming Eagles would have to fight on a ''dirty'' battlefield, or one contaminated with deadly chemical agents.

''The fear is the unknown,'' said First Sergeant Timothy Lincoln, 44, of Knoxville.

''When I go over that berm like I did in 1991, I know I'll feel a little bit of fear.''

In the Gulf War, Lincoln served in an infantry division that was among the first to enter Iraqi-occupied Kuwait.

''There were only about six vehicles in front of me,'' he recalled.

''Our line of trucks stopped for a couple of minutes and I saw the wrapper from a chemical suit float in front of us'' that he assumed had been left by a fleeing Iraqi soldier.

''I thought, `He's going to gas us.''' Although his fears proved unfounded, the scene still haunts Lincoln. He was supposed to retire in December, until ''Uncle Sam had different ideas.''

When the 101st drops into Iraq from its Chinook, Black Hawk, and Apache helicopters, soldiers will be wearing chemical suits, in what's known as MOPP-1, the lowest level of chemical-warfare alert.

Hanging in backpacks and pouches are hoods, boots, gas masks, and a virtual pharmacy of nerve gas antidotes.

It's a drill they practice every day: slap on the mask, don the hood, gloves, and boots, and decontaminate with powder packets. They also practice injecting buddies in the throes of nerve gas poisoning. No one here wants to put those drills to use.

''They have to know if they use chemical weapons on us, they're going to be brought up on war crimes,'' Lincoln said. ''But if it's a dirty fight that they want, I'm here to give them a dirty fight.''