Gaseous chlorine is greenish-yellow, about 2.5 times as heavier than air. Uses include water purification, sanitation in of industrial waste, sewage and swimming pools, bleaching of pulp and textiles and manufacture of carbon tetrachloride, glycol and numerous other organic compounds and phosgene gas. A fresh water source should be available at the field site where liquid sodium hypochlorite is being used so that any contact or spills can immediately be washed off. Protective clothing should be worn while handling this chemical and injectors. Goggles should be worn to protect eyes against splashes.
Chlorine gas is a respiratory irritant which affects the mucous membranes.
It can be fatal after a few breaths at 1000 ppm. Therefore, users of chlorine gas must exercise extreme caution to ensure that it is safely injected. Maximum air concentrations should not exceed 1 ppm for prolonged exposure. Chlorine gas should only be used in well-ventilated areas so that any leaking gas cannot concentrate. This form of chlorine is commonly used in municipal water treatment systems.