Be careful when prepping your pool for this summer season. Nearly 5,000 emergency room visits in the United States are caused by pool chemicals annually, a study conducted by the Centers for Disease Control and Prevention (CDC) finds.

Chemicals are added to pools to keep them safe, controlling acidity and chlorine levels while simultaneously preventing them from becoming overrun with algae and even harmful bacteria. However, these chemicals can also harm pool owners directly, especially if they are not stored or handled properly.

According to the latest CDC Morbidity and Mortality Weekly Report (MMWR), analysts conducted a study of data from the US Consumer Product Safety Commission's National Electronic Injury Surveillance System (NEISS) to estimate the number pool chemical-associated injuries the United States sees annually.

The data, which reflects the number of US pool chemical-associated emergency room visits between 2003 and 2012, showed that none of the injuries ever lead to death.

However, the study revealed that nearly 50 percent of the injuries occurred to someone under the age of 18 and the great majority of these emergency room visits were for poisoning.

Burning and eye injuries were also frequently seen in cases where the chemicals were not handled with the proper protective equipment, despite safety warnings printed directly on bottles and buckets.

Despite their risks, the CDC report also details why pool chemicals are important. A single case in 2012 that sent seven Minnesotans to the emergency room for severe epidermal reaction was later found to be caused by poor monitoring of pool chemistry. Dermatitis caused by water-dwelling bacteria was also considered as a probable cause, according to the Minnesota Department of Health.

Simply keeping tabs on chemical levels is enough to prevent such problems, but the authors also said that state enforcement of this maintenance, at least for public pool facilties, could also help.

"The continuing occurrence of pool chemical-associated health events ... as well as the significantly increased annual incidence of recreational water-associated outbreaks during 1978-2010 underscore the need for regulators at the state and local levels to optimize protection of swimmers and aquatics staff health," CDC investigators concluded.

The report was published in the CDC's MMWR on May 16, as part of the a larger MMWR project for "Recreational Water Illness and Injury Prevention Week."