Description Treated to CCA H4 for in ground use. Applications: most commonly used for boundary fences, sleepers, landscaping, garden edging and boxes. ABOUT TANALISED TREATED PINE. Yes Tanalsed treated pine is safe to use. The preservative chemicals are toxic to insects and fungi, which is, of course, their purpose. Provided the common sense precautions are observed, preservative chemicals do not present a hazard to humans when fixed in the dried timber. Sometimes a white powder will appear on the surface of the timber. This is mostly sodium, solphate, a harmless substance which, if necessary, can simply be brushed or hosed off.
