Chromated Copper Arsenate - Limitation of Human Exposure

Limitation of Human Exposure

A number of countries have reviewed CCA during recent years and have looked at limiting the public exposure to CCA-treated timber by restricting its application in residential situations. These reviews have resulted from increasing public pressures and the possibility of CCA-treated timber posing a health hazard. In response to these pressures the preservation industry in the USA and Canada volunteered not to use CCA for the treatment of residential timber, and on 31 December 2003 the production of CCA-treated wood for such applications became a violation of the manufacturers' labels approved by the United States Environmental Protection Agency (EPA). Exceptions were allowed, including the treatment of shakes and shingles, permanent wood foundations, and certain commercial applications. The regulatory agencies advised however that CCA-treated timber products already in use pose no significant threat to health. Indeed CCA will continue to be used in North America in a wide variety of commercial and industrial applications such as poles, piling, retaining structures and many others.

Following the USA and Canada actions in restricting CCA, similar actions have been taken in other parts of the world, including the EU and Australia. In New Zealand the Environmental Risk Management Authority, reviewing the same data that prompted the actions elsewhere, concluded that there was no reason to restrict CCA use for any applications, but notes that few well-designed studies have been carried out of those using CCA or CCA-treated timber.

CCA timber is still in widespread use in many countries and remains an economical option for conferring durability to perishable timbers such as plantation-grown pine.

Disposal of large quantities of CCA-treated wastes or spent timber at the end of its lifecycle has been traditionally through controlled landfill sites. Such sites are lined to make them impervious in order to prevent losses to the water table and they are covered to prevent rainfall washing out any contained potential toxicants. These controlled sites handle a range of waste materials potentially more noxious than that posed by CCA-treated timber, e.g. paint-stuffs, car batteries, etc. Today, landfill sites are becoming scarcer and disposal of waste materials is becoming economically unattractive. The wood preservation and timber industries are therefore researching better ways of dealing with waste treated timber, including CCA-treated material.

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