Because of its reactivity chlorine is not likely to move through the ground and enter groundwater. Plants and animals are not likely to store chlorine. Effects of chlorine on human health and the environment depend on how much chlorine is present and the length and frequency of exposure. Effects also depend on the health of a person or condition of the environment when exposure occurs. Breathing small amounts of chlorine for short periods of time adversely affects the human respiratory system.
Effects range from coughing and chest pain to water retention in the lungs.
Chlorine irritates the skin, the eyes, and the respiratory system. These effects are not likely to occur at levels of chlorine that are normally found in the environment. Human health effects associated with breathing or otherwise consuming small amounts of chlorine over long periods of time are not known. They are currently under investigation. Some studies show that workers develop adverse effects from repeat inhalation exposure to chlorine, but others do not.