The City of Aliso Viejo was set to ban polystyrene (Styrofoam) cups and food packaging in early 2004 after learning it was manufactured using dihydrogen monoxide. A paralegal working for the city determined that this chemical could “threaten human safety and health” because it’s lethal if inhaled, is a key ingredient in acid rain, and can cause burns when in gas form. Of course, dihydrogen monoxide is water. Sheepish city leaders had fallen victim to a practical joke propagated by computer science professor Tom Way of Villanova University. Way’s satirical dhmo.org website has duped eco-worrywarts since the 1990s. Although the error was caught, other environmental concerns led the city to ban Styrofoam at city facilities and special events anyway. Feel safer?