Difference of CCA & Copper Azole

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Copper chrome arsenic (CCA) treated timber (Hazard Level H5& H6)
Copper chrome arsenic (CCA) treated timber is timber that has been treated with preservative containing copper, chrome and arsenic. CCA treatment prolongs the life of wood, which is why CCA treated timber has so many common uses, including in playground equipment, fences, retaining walls and jetties. Recently concerns have been raised regarding the potential health risks of CCA treated timber.

The preservation process
The CCA process was pioneered in 1933 and is used worldwide. Copper and arsenic in the preservative protect the wood from insect and fungal attack. Chromium (chrome) ‘locks’ the copper and arsenic into the timber and reduces the risk of the chemicals leaching out. The CCA process gives the treated wood a green tint. New Zealand, the USA and Australia are the three highest consumers of CCA treated timber.

Copper Azole - An Alternative to CCA
Copper Azole is a water-based bluish-colored liquid consisting primarily of copper with a small amount of carbon-based tebuconazole and propiconazole fungicide and insecticide. It is wood preservative that prevents fungal decay and insect attack. Copper azole wood preservative is used for treating a variety of softwood species including southern pine, red pine, ponderosa pine, hem-fir and Douglas fir.

Applications of Copper Azole
Water-based preservatives like copper azole leave wood with a clean, paintable surface after they dry. Copper Azole is registered for treatment of millwork, shingles & shakes, siding, plywood, structural lumber, fence posts, building and utility poles, land and freshwater piling, composites, and other wood products that are used in above-ground, ground contact and fresh water as well as in salt water splash (marine) decking applications.

Difference between CA-AG (Above Ground- Hazard Level H3) & CA-GC (Ground Contact- Hazard Level H4) basically is the different dosage of chemical used.

COPPER AZOLE vs CCA

Property	Copper Azole	CCA
Formulation:	Waterborne solution containing copper, tebuconazole and boric acid	Waterborne solution containing copper, chromium and arsenic
Timber appearance:	Initially pale green ageing to green/brown. Weathers to grey over time	Initially pale yellow ageing to pale green. Weathers to grey over time
Environmental:	low metals content in timber and waste	high metals content in timber and waste
Disposal of treated timber:	Burial in landfill or incineration where approved	Burial in landfill only