Shock the Pool Safely

August 10, 2007

I read a report the other day concerning a pool owner who mishandled three pounds of pool shock. The result was a violent reaction that burned the owner’s face and neck and caused respiratory distress. Pool chemical safety is yet another environmental health and safety tip that bears repeating during the Maine summer season.

Look at it this way-- nature uses living organisms and oxygen to clean the water in our lakes and streams, but in pools we use strong chemicals to kill living organisms! There is a myriad of chemicals used to adjust the pH (corrosiveness), color and clarity of the water, all of which need to be properly handled.

But by far the most serious chemical used is the disinfectant chlorine.

Chlorine is used worldwide to disinfect drinking water and to drive chemical reactions in industry. It is an extremely reactive chemical that wants to attach itself to compounds. In doing so it breaks down organic matter (i.e. kills bacteria and microorganisms in drinking water and pools). But it can also recombine with other organic matter and form new compounds, such as trihalomethanes and dioxin, both of which are cancer causing agents.

That’s why government and industry are working hard to minimize the use of this chemical.

As was pointed out at the beginning of this article, with swimming pools the danger lies primarily in the improper storage and mixing of chlorine-containing compounds. (Chlorine is actually a gas that is released when chlorine compounds are mixed with water). Chlorine reacts with the mucous membranes (e.g. eyes, nose and lungs) and forms an acid, which chemically burns the affected areas. This can lead to severe respiratory problems. Chlorine gas also displaces oxygen and causes asphyxiation.

The key to safe use of chlorine is to store it in a dry area away from the other pool chemicals, petroleum and other fuels (even tires) because chlorine can react (oxidize) with these materials and cause a fire. Follow the storage and mixing directions and always mix outside!

There are alternative technologies that are used to disinfect swimming pool water. These don’t require any chlorine, or will greatly reduce the amount of chlorine needed, and are easier on your mucous membranes. Some of the alternatives are: biguanides, chemicals that are also used in some contact lens cleaning solutions and ionizers that electrically produce silver and copper ions that are released in the water to kill organisms. Check with your pool doctor for more information.

So stay cool and safe this summer (what’s left of it) around the old cement-swimming hole, and please follow all the directions in using pool chemicals.

This column was submitted by David McCaskill, an environmental engineer with the Maine Department of Environmental Protection, and a regular contributor to In Our Back Yard on environmental, health and safety issues. In Our Back Yard is a weekly column of the Maine Department of Environmental Protection. E-mail your environmental questions to infodep@maine.gov or send them to In Our Back Yard, Maine DEP, 17 State House Station, Augusta, ME 04333.