More than 1,000 ducks were discovered dead along the Front Range, and wildlife experts say the cause was probably chemicals in water treatment plants, which have stripped water repellency from the birds’ feathers, causing them to freeze to death. The analysis was limited to duck deaths near wastewater plants in early 2007 and early 2008, according to 7News, which points to extended, below-freezing temperatures in those months that iced many other water sources for the ducks. Experts were surprised to discover that chemicals known as surfactants, which are meant to break down surface tension in the water, were behind the deaths. “No one expected it,” says John Wegrzyn, a U.S. Fish and Wildlife Service biologist who worked on the study (via The Denver Post). The chemicals are found in many products—including detergents, fabric softeners, and soda pop—and get into the water when they are disposed.