VVood surfaces treated with hexavalent chromium (Cr VI) compounds are kno\vrı to be more durable than untreated surfaces, and fınishes applied över them perform much more satisfactorily. Although the dichromate \vas originally introduced to reduce the corrosiveness of the dinitrophenol it \vas soon realized that it considerably improvcd fixation and the resistance of the treatment to ieaching, and the dichromate contents have been progressively increased in attempts to further improve fixation. But, a serious disadvantage of the chromium treatments is the toxicity of it. However it is apparendly only the Cr VI is the hazardous form of chromium containing compounds. The object of this study was to examine the İcachabiiity of hexavalent chromium from wood surfaces. Scots pine heartwood blocks (Pinus sylvestris L.) treated with three Chemicals containing Cr VI show that extent of ieaching of chromium from treated wood is small and it amounted from 0 % to 11 % of the chromium introduced. It is therefore likely that, in service, much less than 1 % will be iost from timber vvhich are generaily larger. Fixation of Cr VI is achieved if the treating Chemical is C r 0 3. Total flvation of Cr VI is achieved by heating \vood surfaces treated \vith C rO j for 10 minutes at 135°C. The conclusion that fixation Cr VI on C r 0 3 treated surfaces \vas ahmost complete was based on an observation that small amounts of Cr VI were extracted by soaking in water for 48-hours. Other Cr VI containing Chemicals were not as effcctively fixed on the wood surface by heat treatment (Table-2). The extcnd of İeaching of chromium from treated \vood is small. If the Chemical compounds have reactcd with the wood (fixation) there is no significant danger of contamination of the environment. Even \vith substantial spillage of preservative Solutions at treatment plants and drippings from frcshly treated \vood, the amount of chromium entering the environment is very small, particularly if compared \vith that from other sources such as eiectroplating and the leather industry, and relative to the amounts of chromium already present in the environment. In the treatment plants, providing adequate precautions are taken to prevent the spreading of dust \vhen handling dry po\vder formulations and to prevent contact of the preservative solution \vith skin, there shouid be no unusual dangers associated \vith chromium in \vood preservation.