Borax might kill termites too, there's Borate treatment used by a few
exterminators.  After doing some searching, I read that one can mix Boric
acid with propylene glycol (biodegradable form of anti-freeze), the glycol
helps to saturate the wood.  I was wondering if anyone knows what I could
substitute for the propylene glycol to make it more environmentally safe.

Sharlene