The treatment of wood products with wood preservatives is a necessary and accepted practice for the appropriate use of wood under conditions that favour fungal attack and decay. The environmental risks posed by treated products such as poles and railway ties are not fully assessed, buy within the context of available data, it appears that the contamination of soil, ground water and surface water by products in service is insignificant to undetectable. The socio-economic benefits outweigh and potential risk. This is not to imply that wood preservatives can be taken lightly. They are toxic and contain chemicals that are identified as restricted or hazardous by Federal and Provincial environmental protection acts. The concern, however, is founded on the hazards associated with the manufacture, use and disposal of these preservatives, rather than the risk of environmental contamination by wood products in service.