It's NOT it contains poisons that are released when burned
If in doubt don't burn it, The safest timber to use in your fireplace or
BBQ is natural 100% untreated wood.
"The preservation of timber/wood (tanalising) used to be carried out using a mixture of salts of copper sulphate, potassium dichromate and arsenic pentoxide.
The timber was pressure injected with the preservation liquid in large pressure cylinders, after which it was stacked in the yard while still wet with preservation chemicals. It was not sold till completely dry to reduce contamination.
This was fine in dry conditions, but in the wet, the chemicals could leach out, and the arsenic is transferred to the hands simply from touching the timber.
Children, in particular, are prone to use their hands for eating without washing them first, and can get arsenic poisoning as a result. Food plants grown near tanalised decking can accumulate sufficient chromium to cause symptoms of heavy metal poisoning in anyone eating the produce.
A family in the Antipodes (Australasia) used offcuts of tanalised timber on their barbeque. The cooked meat killed their dog and resulted in the prolonged hospitalisation of the entire family.
Recommendations include avoiding drilling or sawing or use a dust mask if this is unavoidable. Wash thoroughly after touching tanalised timber, and avoid use where people are likely to come into direct contact with the treated timber."
