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A Silent Killer?

As the days start to heat up, millions of Americans will go poolside for some summer fun. Although the water may seem nice and cool, a little-known danger lurks beneath the depths, cautioning some pool-goers against diving in: Chlorine gas.

Chlorine is commonly used to sanitize pools. Its gaseous form can be utilized to remove algae and bacteria from bodies of water. Due to its benefits as a disinfectant and its low-price tag, chlorine has made its way into water treatment systems across the country. In the United States alone, 13 tons of chlorine are produced annually, making it one of the most widely used chemicals in the world. However, the use of this chemical in pools occasionally creates hazardous, or even life-threatening, situations.

Clouds of chlorine gas have been released into public pool areas, poisoning guests in horrifying incidents. These pockets of chlorine form from a mixture of muriatic acid and sodium hypochlorite, common pool purifiers. Chlorine gas is released when these chemicals combine in significant amounts. Although these chemicals are usually diluted in water, improper preparation can cause them to mix in dangerous quantities. Once combined, a cloud of chlorine gas is released into the immediate environment, causing respiratory problems, skin burns, or even death.

Pools are not the only site where the unexpected release of chlorine can cause dangerous events. In 2005, 120,000 pounds of chlorine gas was freed from a freight train, surrounding the town of Graniteville, S.C. In what was later deemed “the worst chlorine gas incident’ in the nation, the cloud killed 9 people and exposed over 1,000 to chlorine gas, causing 550 to be hospitalized for chlorine poisoning and respiratory damage. Recent outbreaks of chlorine clouds have also occurred in recycling facilities, food plants and metalworks. Across the United States, chlorine based accidents are said to occur once every 2-3 days, with approximately 1/3 of these incidents resulting in accidents.

Despite these worrisome figures, measures are being taken to reduce the chance of chlorine gas being released into common public spaces. To prevent accidental mixing, public pools are now tightening security on chemical storage. Education on the proper way to dilute hypochlorite and muriatic acid is being provided to pool employees and homeowners alike. Additionally, municipal fire departments are advocating for ventilation checks for sanitation equipment to catch a buildup of gas before disaster strikes.

Although chlorine gas may pose a threat to those looking to beat the heat, increased awareness of the chemical and its effects are helping to keep thousands safe during the summer months.

If exposed to Chlorine (Courtesy of the CDC):

  • Leave the area where the chlorine was released and get to fresh air. Quickly moving to an area where fresh air is available is highly effective in reducing exposure to chlorine.
  • If the chlorine release was outdoors, move away from the area where the chlorine was released. Go to the highest ground possible, because chlorine is heavier than air and will sink to low-lying areas.
  • If the chlorine release was indoors, get out of the building.
  • If you think you may have been exposed, remove your clothing, rapidly wash your entire body with soap and water, and get medical care as quickly as possible.
  • If you have swallowed chlorine, do not induce vomiting or drink fluids. Get medical attention right away. Consider dialing 911 and explaining what has happened.

Kay, Jane. “Chlorine Accidents Take a Big Human Toll.” Scientific American. Scientific American, 20 Oct. 2011. Web. 15 July 2017.

News, Jane Kay Environmental Health. “Chlorine Accidents Take a Big Human Toll.” Scientific American. Scientific American, 20 Oct. 2011. Web. 15 July 2017.

Purdy, Joy. “Cloud of Chlorine Gas at Florida Pool Sends 5 Kids to Hospital.” WJXT. WJXT, 28 June 2017. Web. 15 July 2017.

Wittkowski, Tony. “Chlorine Gas Cloud at Michigan’s Adventure Caused by ‘two Common Household Pool Chemicals’.”, 11 July 2014. Web. 15 July 2017.

Edited by: Daryn Dever and Ruby Halfacre