The concerns associated with pressure treated lumber stem from the chemical Chromated Copper Arsenate (CCA).
When applied to wood, CCA protects wood from water, sun, and pests, prolonging its functional life. However, arsenic is a know carcinogen and the arsenic in the CCA treated wood can be ingested by hand to mouth contact after touching the wood or the soil below the wood (which may also contain elevated concentrations of arsenic if the deck has been in place for a long period of time).
Children are especially vulnerable while playing on equipment built with CCA treated lumber since they have a tendency to put everything in their mouths. This is why playground equipment constructed with CCA treated lumber has been replaced in many areas. Although there have not been any direct links between arsenic poisoning or cancer and CCA treated wood, manufacturers of the product voluntarily removed it from the market.
According to Health Canada’s Pest Management Regulatory Agency, existing structures made from CCA treated wood do not need to be removed however measures should be taken to protect people (especially children) from the arsenic. A good sealant can be applied to the wood every two to three years to prevent direct contact between the chemicals and any surface that can be easily accessed. There are other types of products on the market that can be used in place of CCA treated lumber. These include pressure treated wood treated with Alkaline Copper Quat (ACQ) or Copper Azole (CBA-A) (these are chemicals which are less toxic than CCA), wood with natural preservatives such as cedar or redwood, or composite materials. Composite materials consist of recycled plastics and wood byproducts. It is more costly than wood, however it requires much less maintenance and is rot, insect, salt, and weather resistant.
