Is anyone familiar with CCA wood preservative treatment for boardwalk applications? I work for a structural engineering firm in NC. We have designed several miles of pedestrian boardwalks and bridges in three phases. The second phase is beginning construction. The contractor is disputing the use of CCA wood preservative for the guard rails and deck boards. I know the EPA is moving away from CCA in residential applications, but can find no documentation that it can't be used for pedestrian boardwalks. I've searched AWPA and AASHTO and haven't found any clear yes or no. The DOT approved our design drawings without commenting on the preservative. The preservative the contractor wants to use has not been approved by the AWPS but has been approved by the SPIB. Any help is appreciated. thanks.