I would assume, since you would be sealing it anyways, it should not cause any problems.
I have heard that there are supposively strong toxic oils in pine (hence, why you should not use it for reptiles or rodents in bedding) which I can understand more with a shredded product, but not as much with a plywood. I was always curious about it though, because I used pine with rodents for years without issues.
Also, Wes, the redwood thing is new to me. Clear me up on this?