Arsenic has been phased out of all treated wood, but what about older stuff still around your home? Is that good? Today you'll learn there's no need for panic even though they've banned it! Here's why. Earlier woods treated with chromated copper arsenate (called CCA for short) were banned because CCA contained small amounts of arsenic, a lethal poison, and even trace amounts were too much if a better preservative could be made without it, especially since it was widely used for decks and to construct children's play equipment. The newer versions--called ACQ (for alkline copper quaternary) and CBA (for copper azole)--both contain more copper instead, which unfortunately is also more corrosive for nails, screws and other hardware. The jury is still out on the ?new? guys. So, what to do with your old treated wood items? The health risk is extremely small if at all and industry thinking generally says to wait and see until the final verdict is in.