This is also from the same site.....good info
" Recycling batteries
According to the EPA, each year over 2 billion used batteries are disposed into solid waste facilities in the United States. This constitutes 88% of the highly toxic mercury and 54% of the cadmium deposited into our landfills. Many kinds of batteries, like those used in digital cameras, can be recycled instead of thrown away. When they wear out, try to take them back to the store where you bought them. Many stores collect the used batteries and then send them to a factory to be recycled. NiCad batteries use Cadmium, a highly toxic heavy metal, that can damage the environment if not disposed of properly. (They should be recycled; not discarded). NiMH (Nickel Metal Hydride) batteries are the most environmentally friendly batteries because they are made from non-toxic metals."