The news story published in yesterday's Courier Journal explains the reasoning behind the sign:
The water in the fountain pools is, like all water, made of two-thirds hydrogen atoms and one-third oxygen atoms.
And as any chemistry student can tell you, there is no health threat from coming into contact with H20.
David Karem, the Waterfront Development Corp.'s executive director, had the signs made to try to keep people out of the water after health officials raised concerns about bacteria in the fountains last year.
However, tests this year show the fountains meeting swimming pool standards.
Karem said he was counting on a lack of understanding about water's chemical makeup, and he thought that suggesting a link to one of the world's most dangerous weapons -- the hydrogen bomb -- might keep them from jumping in.
"I thought that with the word … maybe people would not go there," he said.