How bad is it really to use pressure treated timbers to build a raised bed? My husband worked very hard last night to install one for me, and he got all of the dirt and amendments in it and everything, and then we realized that the timbers used had been treated. We wanted an organic chemical free garden this year. I must add, the timbers have been out in the elements for a little over a year now, if that matters. Should we pull up the timbers and use something else, or just not worry too much about it? Thanks!