The incident happened Saturday in the 900 block of Carolina Way in Sanford.
Deputies said the boy was playing in the water when a family member found him unresponsive.
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Bystanders performed CPR until medical personnel arrived.
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The child was transported to Cape Fear Valley Center and then transferred to UNC Hospital.
Bryan O'Neal, the owner of CPR Carolina, said it's a skill he hopes his students never have to use, but one that can make a major difference in such situations.
"CPR is pretty easy when it really comes down to it. It's obviously not panicking in a very stressful moment, and just push hard, don't be afraid of pushing hard," said O'Neal.
O'Neal added that practicing the skill in non-emergency situations can help prepare people to use it high-stress instances.
"The 100-120 compressions a minute. The song that they always use is 'Stayin Alive' by the Bee Gees, so that's a good pace of doing compressions," said O'Neal.
"If you go too fast, what ends up happening is you don't let the chest come up until you do that next compression. So you do a lot of work and not getting circulation with it. And the whole focus is circulation with the compressions."
When giving compressions, you should find the person's breastbone, use both hands, and call 911 as soon as possible.