Few things in battle are scarier than a gas attack during a ground assault. The air grows thick with toxic mist, and the world shrinks to the view from a hot, sterile mask.
It's the attack most troops have dreaded since the tactic was first used on a large scale at the Second Battle of Ypres over 100 years ago. Chemical warfare was outlawed in the wake of World War I, but it's something that American forces still prepare for.
During a recent mock battle with the Australia military dubbed Exercise Koolendong in Darwin, Australia, Leathernecks from the 1st Battalion, 1st Marine Regiment trainers dropped CS gas into fighting positions to force the troops to deal with a chemical attack in the middle of a firefight.
Photos from the exercise show how difficult it is for troops to fight during a chemical attack and provide an eery reminder of the mustard gas-blanketed battlefields on the War to End All Wars.
1. The assault began with simulated artillery firing in on Marine and allied positions
2. Despite the gas drifting into their positions, the Marines had to stand their ground
3. Range safety officers peer through the gas-filled haze to keep Marines injury free
4. Getting a gas mask on in time to stay alive in the middle of a fight can be a daunting task
5. Despite the restricted vision and discomfort, Marines still have to put rounds down range and keep the enemy at bay
6. Troops take precious minutes testing the air to determine how best to survive the attack
7. It's just as important for medical personnel to practice treating and evacuating casualties during a chem-bio attack
8. As America's potential adversaries look for ways to defeat U.S. troops with unconventional weapons, it's important that the services practice fighting during a chemical or biological attack — no matter how remote the possibility