Two types of chemicals are used in arsenic timber treatments: copper chrome arsenate (CCA) and arsenic trioxide.
CCA is a preservative used to prevent insects, wood rot and wood fungus from damaging timber and timber structures. It is used to treat wood intended for outdoor use, such as telegraph poles and fence palings, in landscaping and in building structures. CCA is commonly applied to timber used outdoors and in the ground to protect it from decay and insect attack.
Arsenic trioxide dust is used by licensed pest control operators (authorised under state or territory legislation) for the post-construction control of termites around buildings.