HazMat teams were called in and there was an emergency evacuation of a nearby elementary school. Chlorine is a Highly Poisonous, Corrosive, and Reactive Gas. As A Military War Gas Chlorine is heavier than air. Its weight is more than twice that of air. This means that it will accumulate in low-lying areas unless there is a good wind.
Chlorine has a sharp, irritating and penetrating odor.
Chlorine has a distinctive green-yellow color. However, the color may not appear when diluted in air unless substantially over lethal concentrations are present. Additionally, gas being released from tanks under pressure will chill the air, perhaps causing white mist or fog. Exposure to chlorine is first revealed by respiratory duress. Common Uses and Applications Chlorine is the ninth highest volume chemical produced in the United States.