Chlorine is a heavy gas with a pungent odor and yellow-green color used as an oxidizing agent. As an effective and relatively cheap source for killing water-borne pathogens, chlorine is the most commonly used disinfectant in U.S. public water sources. It is commonly used in industrial and household cleaning products as well, like household bleach, which is chlorine dissolved in water.
If 98% of U.S. public water facilities disinfect water with chlorine, it must not be dangerous, right? Well, yes. And no. Chlorine in our water keeps us safe by killing disease-causing bacteria such as cholera, typhoid fever, dysentery and many other harmful bacteria. Chlorine also sanitizes (kills bacteria), oxidizes (changes molecular structure), and deters algae buildup in water pipes.
However, chlorine is an indiscriminate killer – of both bad and good bacteria. It is a toxic gas that attacks all living cells. It was the first poisonous gas used extensively during WWI as a chemical warfare agent to cause coughing, vomiting, irritation to the eyes, and even death when used in higher concentrations.
Chlorine kills the good bacteria in our bodies and on our skin. Chlorine causes drying of the skin and hair, as well as reddening of the eyes. Ingesting chlorinated water is believed to leach calcium from our bones. Several studies have shown it to be a carcinogen – meaning it has been linked to cancer.
While the disease-killing element of chlorine is important, too much contact is not good for our bodies. In a perfect world, to protect our bodies, we would filter the chlorine back out of our water before ingesting it or bathing in it. Filtering both your drinking water and your shower water is important to keep your skin, your hair, and the rest of your body healthy.
Chlorine can damage your skin. Even small amounts can be harmful over repeated exposure. When you shower in hot water, the pores of your skin open up, allowing more of this toxin into the skin. Your skin’s natural oils are stripped away, causing dry flakey skin, and even premature aging and wrinkles.
Chlorine can damage hair. As an oxidant, chlorine changes the structure of hair to weaken it. Unlike natural rain water and spring water (famous for leaving hair feeling soft and shiny), water treated with chlorine dries out hair. With tinted or colored hair, the effects are even more obvious, especially with red-tinted hair. Chlorinated water can change the color of bleached or colored hair to a yellow/green. Swimmers refer to this as “swimmers hair.”
The final reason is the chlorine you are inhaling in the steamy shower air. This is entering directly into your bloodstream as you breathe. Just like when you walk into an indoor pool area and are hit with the odor of chlorine in the air, your daily shower causes inhalation exposure to the evaporating chlorine gas in the air.