The popular wisdom is that no one can drown in the Dead Sea because they'll float on the super-salty waters. That's wrong, but it's true that drownings in the Dead Sea are different from drowning deaths in ordinary waters.
The Dead Sea straddles the border of Israel and Jordan. Although the name 'Dead Sea' doesn't promise a good time, it's a fairly popular tourist destination. The concentrated saline is said to be a cure for a number of health conditions, and resorts and medical facilities crowd around the sea's edge. Tourists are encouraged to swim in its waters. There's no fear of sharks. Almost nothing lives in the water. The Dead Sea is landlocked and in the lowest valley on earth. All the minerals of the surrounding countryside get washed into one pool, which in turn gets baked by the sun. This concentrates the salts so much that the Dead Sea is 10 times as salty as the ocean.
All this salt has contributed to the myth that people cannot drown in the Dead Sea. It's true that they can't drown in the conventional way - slipping below the surface of the water. The more salt is dissolved in water, the denser it becomes. Objects in water stop sinking when they displace a mass of water equal to their body mass. In unsalted water, that means a large amount of the body is underwater - all of it for particularly dense people. In dense, salty water, a little body displaces a lot of mass, and most of the body stays out of the water. It's hard to drown a person when most of their body is floating on top of the water like a cork.
An article on an ABC news site even mentions that it's impossible to drown in the Dead Sea, saying "You can't drown in the Dead Sea even if you tried — it's so heavy with salt, it's difficult to put your foot on the bottom." And yet in 2010, 21 people had to be pulled from the sea by life guards. The Dead Sea was named the second most dangerous place to swim in Israel. One big problem is exactly what's described in the ABC article. It's hard to get a foot on the bottom.
Floating on their backs, a person's face is lifted well clear of the water. If they turn over, or if they trip on their way into the sea and fall face down, then the entire back of their body is clear, but their face is pushed into the sea. Anyone who has been in a pool knows that, in regular water, the easiest way to lift the head up and out of the water is to force the feet and lower body down. Easy in fresh water, or in the relatively saltless ocean. Harder when the water keeps forcing every part of the body up. Because the water is dense, it's hard for a person to push an arm into it and turn their body over. The salt of the Dead Sea also contributes to drowning deaths because even a few swallows of it destroys the electrolyte balance in the body. People poison themselves with salt. Massive doses of salt hurt the heart and kidneys and cause the body to shut down.
Spas and resorts around the Dead Sea often employ lifeguards to keep bathers safe. Salt won't do the job, and the myth that no one can drown in the sea certainly isn't helping.