Avoid Rubber Ducks
The rubber duck is a good example of how we're constantly encountering chemicals that aren't healthy for us or for the environment, without even realizing it, as described in the book (and it REALLY IS A REAL book)
Slow Death by Rubber Duck: The Secret Danger of Everyday Things (Counterpoint, 2010).A typical "rubber" duck is actually made from vinyl, a plastic that's highly polluting to produce, and is softened with hormone-disrupting chemicals called phthalates.
Make your house a no-vinyl zone, and especially get rid of vinyl shower curtains and bath toys, which can leach chemicals into the water when they get hot.
Sorry Ernie! You will have to find another bathtime friend!!!