One of the more tempting methods of household hazardous waste (HHW) disposal is to simply throw the product away. After all, it's waste. Although this technique is the easiest, it may also be the most damaging. In a landfill, where that waste is headed, the toxic compounds found in the product will have the chance to seep into the groundwater and pollute the water supply.
While under federal law, HHW can simply be thrown away without any penalty to the individual, the environmental impact it can have is worth a little extra effort on your part. Depending on the waste, just a little can do a lot of harm: A single quart of used oil, for example, can pollute up to 250,000 gallons (946,353 liters) of drinking water because of the heavy metals found in it.
Pouring most liquid HHW down the drain is just as bad, if not worse, since it introduces harmful substances directly to the water supply. To be responsible, you'll want to avoid disposing of HHW in your drain -- with the exception of antifreeze. This waste can be disposed of via your sink, since sewage treatment plants can break down the ethylene glycol in it. Just be sure you allow the water to run while you pour it.
The best way to dispose of HHW is to simply use it up or to find someone else who can put the material or product to its proper use. Paint can be donated to schools or charities, and pesticides can be donated to community gardens, for example. Some areas, like Seattle, Wash., maintain community materials exchange boards, where people list unwanted hazardous waste material they want to give away.
Experts recommend next looking for an official recycling program. Used car oil, car batteries and rechargeable batteries can all be recycled. Check with your local recycling plant or with a company that sells oil or batteries to see if they accept used materials. Some states, like Illinois, stage one-day, semiannual HHW collection drives.
Again, the best way to dispose of household hazardous waste is to use it up. Buy only what you will need to prevent having to store and dispose of hazardous materials. Once you're done with the product, rinse out the container and use it again in its diluted form three times. After three uses, the container should be able to be discarded with minimal impact to the environment or public health.