What are the skin hazards from pool shock?

Fact Checked

If you have not heard what pool shock is about, it is basically a process of adding an additional amount of chlorine into the water to eliminate detrimental algae and bacteria. Always bear in mind that chlorine is a highly reactive as well as a corrosive oxidizer. If an individual enters the water while the water is under pool shock treatment or when the level of chlorine is too high, there is the risk for skin damage and other injuries.


Chlorine is considered as an effective water disinfectant. During pool shock, chlorine is either in solid or gas form or even dissolved in the water. The common form of chlorine used in swimming pools is calcium hypochlorite that is in solid tablet or powder form.

Exposure to pool shock

Pool shock
The damage on the skin from the pool shock treatment can be prevented as long as the individual stays away from the water until the level of chlorine has reduced to normal levels.

The highest risk for skin damage is during exposure to the freshly dissolved chlorine during the pool shock treatment or exposure to the leaking or unadulterated powder. An individual subjected to direct contact to the chemicals especially calcium hypochlorite can lead to severe chemical burns. The areas that are exposed must be washed off right away with water.

How injury develops

The calcium hypochlorite tends to react strongly with the oils and moisture on the skin. In the process known as liquefaction necrosis, the proteins and fats in the skin are destroyed, resulting to deep chemical burns that might have a postponed onset. Additionally, the toxic chlorine gas is also released during this process. Lasting exposure to the low levels of chlorine gas can cause a form of dermatitis called as chloracne.


The damage on the skin from the pool shock treatment can be prevented as long as the individual stays away from the water until the level of chlorine has reduced to normal levels. Since chlorine is broken down by sunlight, the pool shock treatment is usually performed at night to increase the effectiveness. By morning, the level of chlorine is already safe for swimming. Just be alert for any chalk-like pellets, leaked powders and chemicals and avoid any contact. In case of accidental exposure, you will know what to do if you will register for first aid training today.

Considerations to bear in mind

There are alternative water disinfectants available, but chlorine is still widely used. In case the pool shock treatment must be carried out during daytime, the pool operators should post a sign that the pool should not be used.

The high levels of chlorine in the water can dry out and irritate the skin. If the individual feels an itching or burning sensation while swimming, you have to ask the manager the level of chlorine. After swimming, it is important to always rinse thoroughly in order to prevent any residue from causing further irritation the skin and then apply a moisturizing lotion.

Leave a Comment

Your email address will not be published. Required fields are marked *

The information posted on this page is for educational purposes only.
If you need medical advice or help with a diagnosis contact a medical professional

  • All firstaidcprmississauga.ca content is reviewed by a medical professional and / sourced to ensure as much factual accuracy as possible.

  • We have strict sourcing guidelines and only link to reputable websites, academic research institutions and medical articles.

  • If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please contact us through our contact us page.