There's an old joke that plays on the public's scientific illiteracy. It goes like this: there's a dangerous substance that can kill you if you ingest too much of it, and it will interfere with your breathing if you end up immersed in it. Its name? Dihydrogen monoxide. Sounds scary until you spell out the formula, which is H 2 O. Or plain water. The joke has been around for long enough that it's now mostly used sarcastically, as a way of deflating exaggerated claims about other hazardous chemicals.

That doesn't mean, however, that everybody's in on the joke. That was ably demonstrated by two morning DJs who used it in their April Fools' segment earlier this week. According to a local news report, the two have made foolery an annual event but have always managed to keep it family friendly. This year, the duo turned to dihydrogen monoxide, warning their listeners that the local water supply is full of the stuff. Naturally, worried phone calls to the local water authority ensued.

The article quotes a member of the local county utility, who became aware of the broadcast only when nervous customers started getting in touch: "We were fielding calls and letting people know that water was safe." Meanwhile, neither the local authorities nor the radio station management were amused. "My understanding is it is a felony to call in a false water quality issue," the article quotes county spokesperson Diane Holm as saying. The radio station has disavowed the broadcast and suspended the DJs.

The broadcast may have been a joke gone bad, but the underlying problems are anything but a joke. If the public can't even understand a basic chemical formula, then it's probably hopeless to think they'll understand the more complex issues that are typically involved in public health, like complex dose effects and ambiguous epidemiology.