There is a great story on [NPR][1] regarding swimming in Great Salt Lake in general.

> "The Great Salt Lake was like swallowing a battery," Gridley says, "whereas swimming in the ocean was like a glass of lemonade." He warns newcomers about swallowing lake water. "You could end up throwing your guts up."

Generally in the US unless there is a beach or an organized place swimming is usually either not allowed or at your own risk.  Given the quote above I would stay away from the smaller quarry like pools, which may have salination levels closer to the ones in Dead Sea and are more likely to be used as evaporation pool for some sort of industrial operation.

If you still choose to take a swim in one don't be surprised to receive [one of these][2]...

[1]: http://www.npr.org/2013/06/07/188901981/salt-flies-pickled-tongues-a-perfect-great-salt-lake-swim
[2]: http://darwinawards.com/