Polyethylene vinyl acetate (PEVA) plastic has recently become a popular alternative to PVC since it is chlorine-free.
Is PEVA in a shower curtain good or bad?
Finally, if your bathroom has OK or bad ventilation, or you know you're not up for maintenance, choose a PEVA or EVA liner that doesn't off-gas. While these are less healthy than natural fabrics or polyester, they are a relatively low-touch surface, and healthier than PVC or a moldy curtain.