wood fiber insulation boards

Hello

I just have a quick question.

I have some wood fiber insulation boards left over from when we built our house and was wondering if they would be a good source to add in a small hugel.
The data sheet states the only additives are tree sap and less than 0,5% paraffin (wax) and NO formaldehyde.

Thanks

So, I guess it is not such a good idea to use them. I will have to mix them in with the normal garbage bin over time.