Greetings . I’ll chime in and say basically yes, it’s safe to use. Pressure treated wood back in the old days before early 2000’s used to be treated with nasty stuff that wasnt very good for the environment, let alone close contact for pet enclosures.
If you treat your “new” PTW with your sealant it will make things even better. When purchasing your wood, look for very dry, very lightweight boards (these will be older and not just treated).
- “new" pressure treated wood is safe for use for raised garden frames... with a few precautions! Up until 2003, the most common preservative used for pressure treated wood was chromated copper arsenate (CCA), a compound using arsenic as its primary rot protectant.
- Safe for Kids Too - For years, the wood of choice for outdoor play sets was pressure-treated lumber. ... Copper compounds (something called ACQ is one of the most common) are the usual ingredient used to preserve wood now, and it's completely safe. Pressure-treated lumber is an excellent choice for any outdoor playset.Jun 15, 2017
There have been other discussions on here regarding this issue, and the collaborative response is a yes.
Good luck