I didnt see the Aubrey's mentioned in her book--but I probably missed it.
I know Dr. Clark's tests on these are for people with advanced cancer who cant even tolerate a pinch of a stray solvent that entered that batch of shampoo. I t probably wasnt added but could be due to the machinery they use to make it.
I think of all the store bought shampoos--that one and Dr. Bronners' probably has the LEAST amount-- and safer to use than your basic commercial products.
I still am using it- I used to use all the commercial types (high end or low-end) and finally my eyes dont get irritated and red after coming out of the shower.