Storing and Handling Pool Chemicals Safely

What’s more refreshing than swimming in crystal-clear pool water?  It takes chemistry to achieve “crystal clear”—the appropriate use of disinfectants, pH adjusters and algaecides.  Pool water would quickly become a cloudy, hazardous “microbial soup” without pool chemicals, but as with all chemicals, the ones we use in the pool must be treated with a heaping dose of healthy respect.  The following three case studies, taken from recent news reports, illustrate the unfortunate and sometimes tragic results of mishandling pool chemicals.  “Lessons learned” from these examples are highlighted below.

This YouTube video on Pool Chemical Safety provides tips on avoiding pool chemical accidents and injuries.

Keep Pool Chemicals Dry

A hotel in Waldorf, Maryland was evacuated on the morning of March 14, 2015 when two young children complained of eye irritation. The youngsters had been playing in the hotel hot tub, located next to the pool chemical storage area, according to a report in the Washington Post.  A spokesperson for the Charles County Volunteer Fire and EMS Associations later explained that, “A five-gallon container of chlorine tablets had gotten wet, and the odor had begun to spread.”
The “odor” referred to by the spokesperson was caused by a very concentrated solution of the chemical, made as water contacted it.  Heat might have been released when water contacted the chlorine tablets, and the product might have begun to decompose, potentially leading to gas generation. To avoid such chemical reactions, pool chemicals must be kept dry in storage:

  • Store pool chemicals in a location in which they will remain dry and not be exposed to rain, snow or floodwaters.
  • Store liquid pool chemicals low to prevent accidental contact by their leaking onto chemicals stored below them.

Designate Containers for Only One Pool Chemical

A maintenance worker in a senior living home in Cayuga Heights, New York was overcome by fumes last August 9, when he accidentally “put chlorine in a container for muriatic acid,” according to a Syracuse, New York area TV news report.  “Chlorine” in this story likely refers to either solid chlorine-based pool disinfectant or liquid chlorine bleach.  When the chlorine-based disinfectant contacted acid remaining in the container, a chemical reaction occurred that generated chlorine gas, sickening the maintenance worker.  To avoid chemical reactions that may generate unwanted chemical products, never reuse chemical containers, as traces of the original chemical may remain and be reactive with introduced products:

  • Keep chemicals closed in original, labeled containers.
  • Read the entire product label or Material Safety Data Sheet before using or storing chemicals.
  • Dress for safety by wearing appropriate safety equipment, such as safety goggles, gloves and mask.

Never Mix Pool Chemicals

A Buena Park, California pool maintenance worker died of injuries he suffered when he was overcome by fumes generated by chemical mixing in an apartment building garage on February 24, 2015.  The Orange County Register reported fire authorities “…lifted [the man] out of a puddle of yellow chemicals, which omitted a yellow gas…[the man] had severe burns to his back face and respiratory tract, including his lungs.”
Several pool-cleaning chemicals were found at the scene, including chlorine and hydrochloric acid.  The news report speculates that the man might have inhaled toxic fumes, causing him to fall unconscious, knocking over and spilling chemicals as he fell.  A spokesperson for the Orange County Fire Authority stated, “With all pool chemicals we have to make sure they are separated and that they do not mix…. Some chemicals, when they mix, can be deadly.”  This disastrous example contains several lessons:

  • Handle pool chemicals in a well-ventilated area.
  • Open one product container at a time and close it before opening another.
  • Minimize dust, fumes and splashes.
  • Never mix chlorine products with acid; this could create toxic gases.  Even carbonated beverages are acidic enough to react with chlorine products!  Keep food and drinks away from pool chemicals.
  • Never mix different pool chemicals (for example, different types of chlorine products) with each other or with any other substance.
  • Only pre-dissolve pool chemicals when directed by the product label.

Pool chemical accidents in the US lead to thousands of visits to emergency departments each year.1 Yet, many pool chemical accidents are preventable.  Preventing accidents is a matter of maintenance workers and backyard pool owners being armed with safety knowledge.  For important tips on safely using and storing pool chemicals, download or order a free set of pool chemical safety posters at the Centers for Disease Control and Prevention’s website. Further detail can be found in the You Tube video, “Pool Chemical Safety,” which was developed by the Chlorine Institute and the American Chemistry Council, and contains messages based on information from the CDC.

Remember: A healthy respect for pool chemicals will go a long way toward safety in and around the pool!

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Bob G. Vincent is an Environmental Administrator in the Florida Department of Health. He manages Department of Health programs for Healthy Marine Beaches, Safe Drinking Water, Water Well Surveillance and Public Pools and Bathing Places.

1 Morbidity and Mortality Weekly Report, May 15, 2009/58(18); 489-2007.  Pool Chemical—Associated Health Events in Public and Residential Settings — United States, 1983-2007.  On-line, available: