Just when you thought it was safe to come out of the water. Every summer we are warned about the dangers of drowning in backyard swimming pools. Well, now doctors are claiming that kids can experience fatal breathing issues hours after getting out of the water.

Experts refer to this danger as "secondary drowning" as the chemicals used to keep pool water clean can irritate the lungs and cause kids extreme breathing difficulty.

While doctors add the scenario is not common, there are reports of it occurring, as was the case with a young boy in San Diego who recently fell into a backyard hot tub, was quickly retrieved, seemingly unscathed, but then had to be rushed to an emergency room hours later with what was diagnosed as secondary drowning.

"This case is not a total surprise and it can happen, but not in the majority of cases," said Dr. Paul Pepe, chair of emergency medicine at University of Texas Southwestern Medical Center in Dallas. "It's not a common scenario, but it does occur."

Pepe has conducted numerous studies on drowning in Texas and in Florida, where rates are among the highest in the nation. He added that there have been more incidents than reported where long after children are resuscitated from backyard pool mishaps they are rushed to emergency rooms after developing pulmonary edema, sometimes three or four hours after taking in water.

USA Swimming and the Pool Safely campaign recently released some statistics for the early part of 2014 on drowning deaths in pools and spas in the U.S. Thus far, through the end of May, there have already been 95 fatalities involving children under the age of 14 and 74 of those cases have involved children under the age of five. Those organizations do not track deaths from secondary drowning.

A recent Consumer Product Safety Commission (CPSC) report claims there are approximately 400 drownings annually in the U.S. among children under 15, with 75 percent of those involving children under the age of five. The CPSC data also reveals that drowning is the number one cause of deaths among children under the age of 5, with two-thirds of all drownings occurring in the summer months. More than 50 percent of these drownings occur in residential pools, not at the beach, the reports add.

Here's a CPSC checklist for adults to follow to aid pool safety. There's also a pledge to get children involved. Adults should:

* Designate a water watcher every single time children in their care are in or near the water;
* Make sure kids in their care know how to swim;
* Learn CPR; and
* Ensure that all pools have a proper fence, gate, and safe drain covers.

To get children involved in their own water safety, CPSC suggests kids pledge to:
* Agree that they will never swim alone;
* Ask their parents to sign them up for swimming lessons; and
* Promise to stay away from drains in pools and hot tubs.