When Styrofoam is produced or broken down—can it really be broken down?—it releases a chemical compound called chlorofluorocarbons, or CFCs. They enter the atmosphere, where they are broken down by UV rays, and they give off a chlorine atom. These UV rays cause skin cancer and skin problems. When this chlorine atom gets near an ozone molecule, which is 3 oxygen atoms, the ozone molecule breaks apart. The chlorine atom joins an oxygen atom, leaving one oxygen molecule, which is what we breathe. A free oxygen atom breaks apart the bond, making a oxygen molecule, then the same chlorine atom can destroy thousands of ozone molecules. So what? These leftover oxygen molecules can't protect us from the UV rays as well as ozone molecules can. In short, Styrofoam gives off CFCs, which release a gas that destroys the ozone layer.