On Tuesday’s The Early Show consumer correspondent Susan Koeppen explored the dangers of this seemingly harmless youthful beach activity.

Over the July 4 weekend, Rob Duke, 3, was playing in the sand near his parents. He dug a hole on the beach, and, without warning, he went missing.

When she couldn’t find her son, Rob’s mother, Stacy, panicked. “I screamed Rob’s name several times, then I started screaming for anyone who would listen, ‘I can’t find my son. Please help us!”

A Good Samaritan noticed an indentation in the sand by Rob’s parents and began digging. After 10 minutes, the Good Samaritan had located Rob. 

Rob survived this scare, but others have not been as lucky. Nationwide, sand holes have killed dozens of children. Harvard researcher, Dr. Bradley Maron, who has been tracking sand-hole collapses after seeing one on Martha’s Vineyard, says that there have been 52 cases in the past 10 years. Half of these cases have been fatal.

Butch Arbin, who patrols the beaches of Ocean City, Md., believes that sand holes are a bigger problem now than ever before.

“The problem is people just don’t think about it. They would never think. A father would never think (that) he is digging a grave for his own child when he digs a big hole and puts the baby there to take a picture, but (he) is,” Arbin said.

While sand holes can be stable momentarily, any vibration, such as someone walking by, can cause them to collapse. Arbin said, “It happens without warning, and once the hole goes in, it’ll fill in a matter of seconds.”

Koeppen tested the risks of sand holes when she was buried in a three-foot hole. She described the sand as feeling like “a ton of bricks.”

Koeppen said, “The one thing I kept thinking was when I was in there was, ‘I’m a grown woman and I was having trouble breathing and I was panicking and I was thinking, Oh my God, what if there was a little child in there?'”

During sand hole cave-ins, victims have only minutes to be rescued before they suffocate.