A: First of all, alkaline batteries have certainly gotten less toxic through the years. Back in the day, these batteries contained small amounts of mercury. Now they contain zinc, manganese oxide and potassium hydroxide instead.Potassium hydroxide, the nasty stuff you find if you leave your batteries in your flashlight for a few years, tends to leak out of alkaline batteries. While potassium hydroxide may cause respiratory and skin irritation, it's not incredibly toxic.That being said, there's no reason to add metals to our landfill and risk contaminating local water sources. The real issues with toxicity in batteries are all of the non-alkaline batteries out there. Since most of us have better things to do than read battery labels, it's definitely best to recycle all batteries.Most of the other batteries around your house are probably of the rechargeable variety - NiMH (nickel metal hydride), Li-Ion (lithium ion) or NiCad (nickel cadmium). Rechargeable batteries can be replenished hundreds to thousands of times; unfortunately, they are more prone to leaking than alkaline batteries.Nickel metal hydride batteries are nontoxic to humans, though nickel is toxic to plants. Lithium ion batteries are also nontoxic. Nickel cadmium batteries are a different story. Cadmium is highly toxic to humans, animals and plants and is found in both batteries and many electronic devices. In fact, cadmium is banned by the European Union's Restriction on Hazardous Substances. When contained in a battery or electronic device, cadmium is safe, but it's critical that cadmium not end up in our landfills.Finally, car and marine batteries are lead-acid batteries, which are obviously critical to recycle since they contain lead. In fact, Colorado law requires that these batteries be recycled. If your battery is replaced by an auto shop, then you can count on them to recycle it for you.Fortunately, battery recycling in Summit County could not be any easier. Simply collect all of your household and car batteries and take them to one of the following places:• Batteries Plus, 970-245-7000• Hensley Batteries & Electrics, 970-243-6323• Interstate Batteries, 970-434-4237Wondering what happens to your batteries once you drop them off? Batteries are typically shredded and separated into their various components, so that the raw materials can be reused. Examples of products made from recycled batteries include new batteries, stainless steel and rebar.Ask Eartha Steward is written by the staff at the High Country Conservation Center in Summit County, a nonprofit organization dedicated to waste reduction and resource conservation. Submit questions to Eartha at firstname.lastname@example.org.