Copper chrome arsenate, (CCA), is a wood preservative that is fixed into timber and used to protect wood from rotting, fungi and insects, and resist leaching. Freshly treated CCA timber can be identified by its yellow/greenish colour which fades to grey over time.; In the event of a bushfire, structures made from CCA-treated timber can be damaged or destroyed. If you know that you had structures made from CCA-treated timber, when cleaning up the ash, remember that the ash may pose a health hazard if it is swallowed by young children or grazing animals. ; Further information on ash from copper chrome arsenate (CCA) treated timber is provided in the following fact sheet.