As far as I know the only option is to landfill it… unless it’s still in fairly good shape and you can find a neighbor who might be able to re-use it. Treated wood, rairoad ties and utility poles (copper, creosote and arsenic treated) are exempt from the hazardous waste stream even if it fails toxicity testing in most cases (such as your residential use of the product). If your material was made after 2003 or so it more than likely does not contain arsenic, so it’s toxicity is already going to be a bit less… but I still wouldn’t lick it.

Some areas used to burn it as fuel, but the ash is basically a concentrated mix of hazardous material, crushing or shredding increases the chances of leaching issues. Long answer made longer, you’re probably better off to leave it intact and throw it out with your other solid waste (trash). If your quantity is large enough you need a dumpster, you should still be o.k, but obviously confirm with the dumpster company that they are cool with you filling the dumpster with treated lumber. Some may be a bit gun shy about allowing it… Landfills can be a pain sometimes when trying to get rid of items that are not considered hazardous but seem like they probably should be.

If they try to charge you a hazardous waste rate, look around a bit more… it’s not hazardous waste.

If you are interested in this kind of stuff you should check out the Indy Earth Hour Campaign