About 5 million dollars worth of structural timbers are sold annually in Australia for use in the marine environment. CSIRO is conducting several marine tests on preservative-treated wood which have been in place for 9 to 26 years. The performance of timber varies in different hazard zones which are themselves distinguished by different species and activities of marine borers. The piling options likely to produce service lives of at least 20-30 years for a particular hazard zone are listed.