Chlorine gas is poisonous, and exposure can lead to chronic and even fatal illness. Understanding the toxic effect of chlorine gas is important for preventive measures and for recognition when a person is affected. Exposure to the gas usually occurs in industrial settings, but chemical spills, landfills and toxic wastes can also expose just about anyone to the toxic gas.

Chlorine gas is very dangerous to the respiratory tract. Inhalation of chlorine gas in high concentrations results in liquid droplets of chlorine entering the body. This can cause bronchitis and fluid within the lungs, or pulmonary edema. Acute amounts of the gas results in the onset of pulmonary edema within a two-day period. Exposure can cause other non-fatal symptoms like coughing, breathing difficulty and chest tightness. Vomiting, spitting up blood, skin discoloration are other symptoms. Reactive Airways Dysfunction Syndrome, which produces asthma-like reactions, can result as well.

Gas exposure to the eyes causes a severe reaction. Burning, stinging, and irritation will result shortly after. Redness of the eye is a common symptom associated with exposure to chlorine gas. High concentration of chlorine gas exposure will result in watering of the eyes. Chlorine in its gas form is less toxic than in its liquid form. Liquid particles of the chlorine within the gas can cause permanent eye damage including frostbite of the eye, eye burns in the first and second degree, and blindness.

Chlorine gas exposure within the mouth and throat causes coughing and throat and mouth dryness. Breathing difficulty and chronic coughing will only result at high concentrations of chlorine gas. Headache, vomiting and fainting occur after a long exposure at high concentrations.

Skin exposed to chlorine gas can become frostbitten. The gas fuses into the skin cells and under the epidermal layer. Symptoms include prickling and an itching sensation. Numbness around the exposed and affected skin will develop. In severe exposure cases, the gas will cause a burning sensation and eventual tissue death. If the skin cells do survive the initial or chronic chlorine gas exposure, it can take on a yellow or waxy appearance.