This is the reason to wear a mask when cutting this stuff, these pallets are all used and coated in various amounts of whatever, in an effort to not breath this cocktail of chemicals in you really should wear a mask, You don't want this stuff floating around in you. I am using all of the pallet wood outdoors as well, you wouldn't really want it installed indoors for the same reasons. I think for my rain-screen wall it will be ok.