CS, which stands for 0-chlorobenzalmalononitrile, is actually a white solid powder usually mixed with a dispersal agent, like methylene chloride, which carries the particles through the air. CS is more stable, more potent and less toxic than the more commonly used CN agent. Physical effects of this tear gas are felt almost immediately. In some cases there can be mucus secretion, nausea and vomiting, also burning sensations on the body in places touched by the hands.
Recovery quickly follows after an affected person is immersed in fresh air.
CS gas is not known to have caused any deaths or permanent injuries, however its use has been banned in some American military operations. Police training manuals warn that CS should be used out of doors, to disperse crowds, and CN used indoors, to force people outside. Toxicologists describe the effects of CS as incapacitating, and certainly not the agent of choice if a fire is anticipated. Although the exact answer to this question may never be known, there are at least two reasons why CS probably did not worsen the situation during the seige. First, on the day tear gas was deployed there was a steady 17 to 24 mph wind, which, combined with gaping holes in the compound made by the tanks, created a situation where much of the tear gas was blown away.