Home made reptile rack

Hi there i recenly was given a reptile rack from a friend. I noticed the rack is made from douglas fir wood. Ive had the snakes in there for a week with no issue. Im worried with the whole pine maybe bad that this rack could harm the snakes. The rack bins are fully enclosed so no contact with the wood at all. Should i paint this rack or just leave it since theyre in their enclosed bins?

They’re fine. No need to paint it.