oh i looked into this and didn`t find anything...we now have a bright GREEN plastic mat that i washed and washed before putting it in. it does look good though!
i`ll look into this to see if there are any other options.
I've been finding what are labeled as 100% latex mats. Are they natural latex vs synthetic? Dunno. They are sort of off-white, and don't have a strong odor (and even natural latex does have some odor, our granola pillows and mattressed do have some odor). I look for ones that are bath size, to provide more coverage in the tub, as our girls go in at the same time.
I would definitely avoid PVC if I could. Maybe IKEA has something?