Paragraph 4b) of Annex XVII to REACH concerning arsenic compounds provides for a list of applications for which wood treated with CCA may be used. This is not a list of examples of possible uses but an exhaustive list of authorised applications. It flows both from the actual wording of those provisions and from their objective that the derogation provided for in paragraph 4 must necessarily be subject to a strict interpretation, as confirmed by the Court of Justice (case C-358/11, pp. 40-43).
Consequently, wood treated with CCA cannot be used for other applications than the ones listed in paragraph 4 b). Wood treated with CCA can, therefore, not be used for railway sleepers installed above ground.